NOTE–Mixed Signals: An Analysis of the Third-Party Doctrine as Applied to Warrantless Collection of Historical Cell Site Location Information
by Caitlin Campbell*
“For the Fourth Amendment protects people, not places. What a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection. But what he seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected.”
– Justice Potter Stewart
What phone numbers have you dialed in the past 72 hours? How often do you send text messages to an out-of-state phone number? Did you drive to your doctor’s office yesterday? How many times have you driven to a fast food restaurant in the past month? Have you visited any of your friends’ or family members’ houses recently? Have you stayed overnight somewhere other than your home during the past 127 days? These questions may seem like invasions of privacy. Reasonable individuals do not expect strangers to inquire into such details of their lives. Reasonable individuals certainly do not expect the government to have access to historical caches of this data tracked over months of their lives. However, most individuals are unaware that the government may obtain and review any of this information about anyone, without a warrant, and without even probable cause to suspect that a crime has been committed. Under the Stored Communications Act, courts may issue orders authorizing governmental entities to require electronic communication service providers to disclose customer communications or records when the governmental entity can show that it has “reasonable grounds to believe that the . . . records or other information sought, are relevant and material to an ongoing criminal investigation.” By allowing the government to compel cell service providers to turn over this historical cell site location information, the Stored Communications Act empowers the government to search through months’ worth of location information, revealing intimate details of one’s associations and patterns of movement without requiring a warrant or a showing of probable cause.
The Fourth Amendment to the United States Constitution provides that “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated.” Generally, a search is considered to be reasonable if a law enforcement officer conducted the search after obtaining a warrant that was based on probable cause that a crime was afoot, was issued by a neutral magistrate, and particularly stated the places or people to be searched and the things or persons to be seized. Over time, this warrant clause in the Fourth Amendment has been demoted from a requirement for reasonableness to a mere “touchstone” of reasonableness. Additionally, courts have carved out many exceptions to the warrant requirement and Fourth Amendment protections. The United States Supreme Court has articulated the third-party doctrine, which states that an individual loses any expectation of privacy in information that he or she voluntarily turns over to a third party. The rationale behind this doctrine is that government intrusion into information conveyed to a third party does not even qualify as a search and therefore is not subject to any Fourth Amendment protection. The third-party doctrine also justifies the provisions of the Stored Communications Act that allow the government to compel electronic communications service providers to share stored electronic data in absence of a warrant.
This paper will provide an overview of the existing third-party doctrine and examine the key cases in which the United States Supreme Court developed the doctrine. Section I will review the origin and early development of the third-party doctrine. Section II will acknowledge cases in which the third-party doctrine has played a useful, logical, and valid role in seeking truth and justice. To highlight the disagreement among courts over how the third-party doctrine should apply, Section III will consider a recent case in which use of the third-party doctrine to obtain cell site location information seems unfairly invasive. Section III will also examine some compelling arguments from dissenting judges and justices in cases applying the third-party doctrine. Section IV will look critically at United States v. Jones, paying particular attention to the question Justice Scalia left open regarding surveillance through electronic means and diving deep into Justice Sotomayor’s concurrence to speculate as to how her opinion may prove to be persuasive in shaping new Supreme Court doctrine as society’s expectation of privacy in electronic data grows. Considering Justice Sotomayor’s stated view, Section V will analyze United States v. Carpenter, a case recently argued before the United States Supreme Court, which addresses a warrantless search and seizure of historical cell site location information. To conclude, this paper will consider alternative applications of the third-party doctrine to properly account for society’s modern expectation of privacy in cell phone data and will propose a new rule requiring the government to obtain a warrant based on probable cause before accessing any historical cell site location information.
To understand the origin of the third-party doctrine, one must go back to the 1967 Katz v. United States decision in which the Court shifted its definition of a search within the meaning of the Fourth Amendment from purely a notion of trespass to one of a reasonable expectation of privacy. In that case, the Court held that a government wiretap of a public phone booth qualified as a search because it violated the defendant’s reasonable expectation of privacy. The rule that developed out of Katz is two-pronged: the individual who was searched must have exhibited a subjective expectation of privacy, and society must be prepared to recognize that expectation as reasonable. This test is the indirect foundation of the third-party doctrine.
Articulating the Third-Party Doctrine
Two seminal cases solidified the third-party doctrine as a Supreme Court-authorized exception to Fourth Amendment protections. In United States v. Miller, the Court held that an individual had no legitimate expectation of privacy in bank records kept in accordance with the Bank Secrecy Act. Even though the individual may have believed that the bank would hold these records in confidence or, at most, only share them for limited purposes, this did not constitute an expectation of privacy that would prohibit the government from obtaining the financial records from the third-party bank. Because Miller had disclosed his financial transactions to his bank, the Court held that he had no privacy interest in anything that third-party institution chose to do with its records of those transactions. In Smith v. Maryland, the Court held that installing a pen register to collect the phone numbers dialed from an individual’s phone was not a search within the meaning of the Fourth Amendment, and therefore no warrant was required to collect those numbers, since the data containing those numbers had been turned over to the phone company, a third party.
Further Defining Expectations of Privacy
After Katz v. United States established the expectation-of-privacy test for assessing the reasonableness of searches, the Court began to examine the warrantless use of technology that enhanced law enforcement’s surveillance capabilities. Two cases in particular evaluated the constitutionality of warrantless location tracking using beepers.
In United States v. Knotts, the Court followed Fourth Amendment jurisprudence in holding that there is a lower expectation of privacy in the movements of a vehicle on public streets. In that case, law enforcement officers cooperated with a seller of chloroform to place a beeper inside a chemical container to be sold to an individual of interest. Using the signal from the beeper inside the container and maintaining visual surveillance of the individual’s vehicle, law enforcement officers tracked the chemicals and the individual to a remote cabin the woods. The officers used this information to obtain a search warrant for the cabin, where they discovered a drug manufacturing operation. Knotts argued that since the monitoring of the beeper’s location was warrantless, all evidence based on that monitoring should be suppressed. Because the government did not use the tracking information from the beeper to ascertain anything that would not have been available through visual surveillance of the suspect from lawful vantage points, the Court held that the use of the beeper constituted “neither a ‘search’ nor a ‘seizure’ within the contemplation of the Fourth Amendment.” The Court specifically pointed out that one has no expectation that his movements on public highways will not be tracked without consent. Knotts anticipated the danger such governmental power could pose on liberty and argued that allowing this type of tracking could lead to “twenty-four hour surveillance of any citizen of this country.” The Court did not recognize a dangerous abuse of power in Knotts, but it did warn “[i]f such dragnet-type law enforcement practices as respondent envisions should eventually occur, there will be time enough then to determine whether different constitutional principles may be applicable.”
In United States v. Karo, the Court held that there was no violation of Fourth Amendment rights when the government installed a beeper into a can of ether to be sold by a government informant to suspects. While the Court applied the Knotts precedent to determine that there is no reasonable expectation of privacy in one’s movements on public thoroughfares, it held that warrantless monitoring of a beeper that was within a home to obtain information not observable from a lawful vantage point outside the home violated the Fourth Amendment rights of individuals with privacy interests in the home.
One must note that although the two beeper cases help to define reasonable expectations of privacy, both Knotts and Karo involve surveillance actions taken by the government without the aid of third parties. However, these cases lay the groundwork for cases in which the government used technology to enhance surveillance capabilities.
Expectations of Privacy and Surveillance Technology
As surveillance technology advanced beyond beeper trackers, courts had to address Fourth Amendment searches using cell phones and global positioning systems. In Riley v. California, the court addressed whether law enforcement officers could search the contents of a recent arrestee’s cell phone under the search-incident-to-arrest exception to the warrant requirement. The logic behind the search-incident-to-arrest exception was that individuals who have been arrested have a lessened expectation of privacy. That idea, coupled with the government’s interests in protecting officers’ safety and preventing the destruction of evidence led to this exception that allowed law enforcement officers to search containers found on a recent arrestee to check for weapons or evidence of the crime of arrest. Because neither of the interests justifying a warrantless search-incident-to-arrest would be served by a warrantless search of the contents of Riley’s cell phone, the Court held that the contents of Riley’s cell phone were protected by a Fourth Amendment expectation of privacy, and law enforcement officers needed a warrant based on probable cause to search through the phone.
In 2012, the United States Supreme Court addressed the question of whether the attachment of a global positioning system to an individual’s vehicle, and subsequent use of that device to monitor and track the vehicle’s movements on public streets, constituted a search within the meaning of the Fourth Amendment. In Jones, the government did not have a valid warrant to place the GPS tracking device on Mr. Jones’s vehicle. Once the device was attached, law enforcement officers collected over 2,000 pages of surveillance data listing the movements of that vehicle over twenty-eight days to within an accuracy of 50 to 100 feet. The Court ultimately relied on the older trespass standard to determine that this action was a search because the government had physically occupied private property (the vehicle) for the purpose of obtaining information.
Although both Riley and Jones dealt tangentially with cell phones and location data, neither of those cases addressed the constitutionality of the collection of location data itself through cell phones. Nonetheless, these cases are important pillars of privacy interests, and they leave open some questions about the reasonableness of electronic surveillance.
In some cases, the use of the third-party doctrine is a useful, logical, and valid constitutional exercise. In an effort to stop crime, it is undoubtedly helpful to law enforcement to be able to access information through third parties without a search warrant in order to establish the requisite probable cause for an arrest warrant. Following Supreme Court jurisprudence, it makes sense that the government can access information in which individuals have no reasonable expectation of privacy. The question then becomes whether an individual has a reasonable expectation of privacy in the information.
In recent years, cell site location information (“CSLI”) has become a frequently used tool for law enforcement officers in placing suspects within the geographic region of a crime scene. Cell site location information is data showing which service towers a cell phone has connected to by broadcasting its location to nearby cell towers. Cell service providers store this data for their own business purposes of evaluating and improving their operations and promoting efficiency. This data is not used for real time tracking, but rather for looking at historic records of location. The Stored Communications Act (“SCA”) provides guidelines for the disclosure of this and other types of communication information by providers of electronic communications to government entities.
Historical Cell Site Location Information Cases
In deeply divided opinions, three U.S. Courts of Appeal have held that there is no right to privacy in cell phone data held by a cell service provider and have applied the third-party doctrine to such data, allowing the government to obtain it without a warrant. Another U.S. Court of Appeal has held that it is up to a federal magistrate to decide whether to require a warrant for government access to data held by a cell service provider.
In 2010, the Court of Appeals for the Third Circuit held that although the burden on the government to obtain a court order compelling production of an individual’s cell site location information was less than establishing probable cause, it was within the Court’s discretion to require the government to obtain a warrant before ordering the provider to produce a customer’s CSLI. In explaining its decision, the Court focused on the compulsory nature of the collection of CSLI, saying that cell phone users do not “voluntarily” share their location with cell service providers “in any meaningful way.” The Court was also persuaded by the Electronic Frontier Foundation’s argument that cell phone customers are unlikely to realize that their providers collect and store their CSLI.
Three years later, the Court of Appeals for the Fifth Circuit reached the opposite conclusion, holding that cell phone users “understand that their service providers record their location information when they use their phones.” The Court looked back to Smith in determining that if landline users understood that the phone companies recorded the numbers they dialed back then, then cell phone users understand that their cell service providers record their cell phone activity at least to the same extent. In that case, the Court disagreed with the Third Circuit and held that a magistrate judge did not have discretion to require a warrant before issuing an order under the Stored Communications Act. The Court also held that the lesser “specific and articulable facts” standard outlined in the SCA to compel cell service providers to produce historical cell site information was not per se unconstitutional as a violation of the Fourth Amendment probable cause standard.
The Court of Appeals for the Eleventh Circuit also applied the third-party doctrine to historical CSLI in United States v. Davis in 2015. In this case, the government introduced CSLI records spanning a 67-day period in an attempt to place Davis in the vicinity of the sites of a string of seven armed robberies over that two-month period. Though Davis challenged the constitutionality of using this information in violation of his Fourth Amendment expectation of privacy, the Court applied Miller and Smith directly and held that Davis had “no reasonable expectation of privacy in certain business records owned and maintained by a third-party business.”
In 2016, the Court of Appeals for the Fourth Circuit held that obtaining historical cell site location information from a cell service provider without a warrant did not violate the Fourth Amendment. The Court explained its rationale practically, falling in line with other circuits in holding that individuals have come to expect that cell service providers will “at a minimum, route outgoing and incoming calls and text messages.” The Court logically explained that cell phone users exhibit their knowledge that location or proximity to a cell tower matters when they move outside in an attempt to “get a signal” or warn someone on the line that they may drop the call as they pass through an area with poor service. When this logic is widespread in modern society, it is difficult to refute this argument with claims that cell phone users are unaware that cell service providers collect and use location information in providing their service.
Proponents of continuing to apply the third-party doctrine to historical cell site location information argue that the Supreme Court would undermine or erode decades of precedent if it were to carve out an exception for CSLI held by third-party providers. They point to the need to preserve the third-party doctrine to maximize police efficiency, citing the Knotts opinion, “[w]e have never equated police efficiency with unconstitutionality, and we decline to do so now.” In order to prevent criminals from using technological advances to circumvent the law, law enforcement officers must be allowed to use technological advances to their advantage in ferreting out crime. Those who wish to keep CSLI accessible to government through the third-party doctrine also suggest that Congress, not the Court, is the better entity to address societal concern about the privacy of CSLI. Congress is better suited to respond to fast-paced and unforeseen technological advances, as it did after Miller by enacting the Right to Financial Privacy Act, which allows banks and other financial institutions to challenge subpoenas and to narrow the scope of government inquiry, and after Smith by enacting the Stored Communications Act, Section 2703(d) of which limits government requests for CSLI.
In some cases, despite their holdings, applying the third-party doctrine seems to unfairly invade areas of where one would expect privacy. Because the courts that have addressed historical cell site location information have all applied the third-party doctrine and allowed governmental entities to obtain CSLI without a warrant and without a showing of probable cause, there is not an actual circuit split on this issue. However, each of those decisions has been fractured, sparking concurrences, concurrences in judgment, and dissents.
One recent case in the D.C. Circuit set a new boundary on the third-party doctrine as applied to cell phones and CSLI. In this latest Jones case, law enforcement officers used a “Stingray” device to simulate a cell service provider’s cell tower, allowing them to locate a cell phone and to intercept calls and texts to and from targeted cell phones. Experts hired by both parties testified that the “Stingray” device prevents cell phones in its vicinity from connecting to any other innocuous cell tower. The device exploited a weak spot in the security system of a cell phone and coerced the phone to connect with the simulator, divulging information that allowed the government not only to track the phone’s movement, but also to locate the cell phone user. The Court held that warrantless use of the“Stingray” device invaded Jones’s reasonable expectation of privacy and was therefore an unconstitutional search in violation of the Fourth Amendment. Although this case did not directly rule that CSLI was protected from the third-party doctrine, it did set a clear boundary of what type of action is beyond the scope of the doctrine. After this case, the government should think twice before trying to run an endgame around the statutory parameters already set for obtaining CSLI. This case clearly turned on the fact that law enforcement officers tried to gather CSLI by simulating a cell tower rather than by going through the simple procedure to request CSLI data from third-party providers’ cell towers.
In a concurrence with the Davis opinion, Judge Robin Rosenbaum highlighted a key argument of the dissent and of many who oppose allowing warrantless access to CSLI through the third-party doctrine by pointing out that “[i]n our time, unless a person is willing to live ‘off the grid,’ it is nearly impossible to avoid disclosing the most personal information to third-party service providers on a constant basis, just to navigate daily life.” This undercuts the assertion that cell phone users knowingly and voluntarily convey their information to third-party service providers. Such conveyance cannot be voluntary if society does not afford the option to forego a device that automatically conveys one’s sensitive location information. This argument is an extension of Justice Brennan’s dissent in Miller, in which he noted that economic life in contemporary society necessitated a bank account.
Justice Marshall reiterated this point in Smith, saying, “unless a person is prepared to forgo use of what for many has become a personal or professional necessity, he cannot help but accept the risk of surveillance.” Regarding government surveillance through the third-party doctrine, Justice Marshall and Justice Brennan subscribed to the theory that one does not give up all of one’s privacy interest when disclosing something to one party for a particular purpose. This idea that an individual can maintain some privacy interest even in information conveyed to a third-party appears in other lines of Supreme Court and federal appellate precedent. Most notably, the Court of Appeals for the 6th Circuit held that an individual has a reasonable expectation of privacy in his emails even though they were sent via a third-party Internet service provider and that the government violated his Fourth Amendment rights by failing to obtain a warrant based on probable cause before compelling the third-party provider to produce the emails. Warshak went so far as to declare that to the extent that the Stored Communications Act allows the government to access emails and their content without a warrant based on probable cause, the SCA is unconstitutional.
Though courts continue to apply the third-party doctrine to personal electronic data, there is confusion and disagreement as to how and when the third-party doctrine should apply to electronic data, especially cell site location information.
Where Jones Left Off
The Jones case left open a question about the constitutionality of warrantless electronic surveillance. In the majority opinion, Justice Scalia wrote, “It may be that achieving the same result through electronic means, without an accompanying trespass, is an unconstitutional invasion of privacy, but the present case does not require us to answer that question.”
As noted above, in this case, the Court held that installing a global positioning device on a target’s vehicle and using that device to monitor the vehicle’s movements was a search under the Fourth Amendment and an unconstitutional one, since there was no warrant. Although all nine justices agreed on this holding, they were split when it came to the reasoning that justified the holding. Four justices decided the issue solely on the basis of trespass. Four other justices concurred in judgment, but decided the issue solely on the basis of the reasonable expectation of privacy test formulated in the Katz opinion. One justice, Justice Sotomayor, joined the majority’s opinion, deciding the case on trespass because she believed that it was the narrowest grounds on which the case could be decided. However, in her concurrence, she conceded that she believed the Jones fact pattern also constituted a privacy violation, as the other four minority justices pointed out.
Justice Sotomayor suggested that the Court may need to reconsider the third-party doctrine in light of new and changing technology. She wrote:
It may be necessary to reconsider the premise that an individual has no reasonable expectation of privacy in information voluntarily disclosed to third parties. This approach is ill suited to the digital age, in which people reveal a great deal of information about themselves to third parties in the course of carrying out mundane tasks.
She went one to express concern that continuous location information like that collected in Jones can give the government a precise and comprehensive record of an individual’s movements, which provides enough detail to allow for speculation about personal associations of all types. Having voiced this opinion, Justice Sotomayor may prove to be a decisive player in shaping new Supreme Court doctrine as society’s expectation of privacy in personal electronic data grows. If her hesitation in Jones is indication that she is skeptical of the reasonableness of tracking using a tracking technology limited by the government’s ability to physically place it on a vehicle, that skepticism is likely magnified in cases in which the government collects cell site location information without any physical trespass.
In 2017, the United States Supreme Court granted certiorari to a case from the Sixth Circuit, United States v. Carpenter, to address this divisive issue of collecting cell site location information without a warrant. The Court heard oral arguments in this case on November 29, 2017. In Carpenter, one of four men arrested following a string of armed robberies confessed to the crimes and gave FBI agents the cell phone numbers of the other participants. Using those phone numbers, the FBI obtained 127 days’ worth of cell site location information for Timothy Carpenter’s cell phone, showing that he had used his cell phone within a half-mile to two mile radius of several of the robberies at the times they occured. Carpenter challenged the government’s use of the business records of his cell service provider as violating his Fourth Amendment rights. The Court of Appeals for the Sixth Circuit focused on the distinction in Fourth Amendment cases between content of a communication and the information necessary to convey the communication. It held that the content of a cellular communication is protected under the Fourth Amendment, but information that a service provider uses to route that communication is not protected.
Before the United States Supreme Court, Carpenter has distinguished his case from both Riley and Jones in an attempt to limit the third-party doctrine’s application to cell site location information. While Riley dealt with protected content on a cell phone, Carpenter involves what has traditionally been known as incidental transmittal data. To bolster his claim that CSLI should be protected, Carpenter argues that in light of modern technology, “content as a category is both under-inclusive and unadministrable.” Drawing from the concurrences in Jones, he points out that although the information at hand is not the content of communication, location over time in public has been protected as sensitive and revealing personal information.
Carpenter’s strongest arguments emphasize the privacy interest at play and ask the justices to evaluate how reasonable an expectation of privacy in location tracked through one’s cell phone is in society today. Of course the government has argued that the Court continue to apply the third-party doctrine as a standard society has come to understand – that one forfeits any privacy interest in things communicated to a third party. One of Carpenter’s stronger rebuttals is that this cell site location information was not voluntarily communicated to the service provider in any meaningful way, much like in Miller. By stressing the magnitude of private information that could be available for government surveillance without a warrant and by emphasizing the compulsory manner in which cell site location information is collected, Carpenter might persuade five justices that CSLI should be protected by the Fourth Amendment and no be accessible through the third-party doctrine.
In the Carpenter case, the Court has an opportunity to build on the protection of location data established in Riley and Jones. Some scholars have predicted that the Court will cling to the reasonable-expectation-of-privacy line of precedent, resulting in a ruling that, like Robinson, will need subsequent realignment and interpretation. The Carpenter case itself results from a plea for the Court to determine whether it makes sense to apply an old doctrine to new and unforeseen technology. However, one scholar proposes a straightforward method of analysis. If the Court were to break this analysis down into simple steps and apply the Fourth Amendment directly, it would have to determine that this search of digital data is the equivalent of a search of papers within the meaning of the Fourth Amendment in that both papers and digital data are commonly used media to store and communicate information. The analysis then turns to whether the search was reasonable. Although courts have created many exceptions to the warrant requirement for reasonableness, “it is a cardinal rule that . . . law enforcement . . . use search warrants wherever reasonably practicable.” This straightforward analysis would lead the Court to rule that cell site location information is protected by the Fourth Amendment.
Another scholar suggests that in place of the third-party doctrine, there should be a “human eyes” standard, which would negate large scale computer searches through masses of data only for the purposes of the Fourth Amendment. This theory rests on the idea that no search or seizure occurs unless human eyes actually see the communications. Without a search or seizure, Fourth Amendment protections do not apply. However, this proposal accepts that computers may still collect and store massive amounts of personal information about citizens.
In order to avoid unconscionable application of the third-party doctrine, the court needs to reevaluate the doctrine in light of modern technology and provide greater protection for the private information that can be collected unwittingly from cell phones. The Court should rule that obtaining cell site location information requires a search warrant with the standard showing of probable cause. Since cell phones now contain substantial amounts of sensitive personal information, and since many daily activities such as grocery shopping, banking, and navigating now utilize cell phone applications for speed and convenience, it is unlikely that people will become less attached to their cell phones with time. As technology advances, location tracking will undoubtedly become more precise, and thus more powerful in the hands of the government. In order to ensure continued Fourth Amendment protection from unreasonably invasive searches, the Court should require the government to obtain a warrant for CSLI.
There is already a procedure for requesting cell site location information under the Stored Communications Act. A government entity may request CSLI without first notifying the customer if the government can offer “specific and articulable facts showing that there are reasonable grounds to believe that the contents of a wire or electronic communication, or the records or other information sought, are relevant and material to an ongoing criminal investigation.” This standard is similar to a reasonable suspicion standard, a lesser showing of suspicion than the probable cause requisite for a warrant. Since the Stored Communications Act already requires a standard of suspicion and a formal request for a court order to compel cell service providers to turn over the CSLI, it would be a simple fix to raise that requisite standard of suspicion to probable cause, and require a warrant instead of a request for a court order to compel. This minor change in the statute would provide the protection from unreasonable searches that the Fourth Amendment promises. Critics like Justice Alito may say that Congress is better suited than the Court to adopt new rules in response to technological advances; however, it would be much easier for Congress to create rules to match modern technology if the Court would recognize that the third-party doctrine as applied in Smith no longer makes sense in cases involving communications technology.
*Caitlin Campbell is a 2019 candidate for a Juris Doctor degree from the UA Little Rock William H. Bowen School of Law and a Master of Public Service degree from the University of Arkansas Clinton School of Public Service.
 Katz v. United States, 389 U.S. 347, 352 (1967).
 Stored Communications Act, 18 U.S.C. § 2703(d) (2017).
 U.S. Const. amend. IV.
 Id. and see, e.g., Andresen v. Maryland, 427 U.S. 463, 492 (1976).
 See Katz, 389 U.S. at 360; Riley v. California, 134 S. Ct. 2473 (2014).
 See, e.g. United States v. Miller, 425 U.S. 435 (1976); Smith v. Maryland, 442 U.S. 735 (1979).
 Smith, 442 U.S. 735.
 Stored Communications Act, §§ 2701 – 2703(d).
 United States v. Jones, 565 U.S. 400 (2012).
 United States v. Carpenter, 819 F.3d 880 (6th Cir. 2016) (cert. granted 137 S.Ct. 2211, June 5, 2017).
 Katz v. United States, 389 U.S. 347 (1967).
 Katz, 389 U.S. at 361 (This two-part test is articulated in Harlan, J.’s concurrence).
 United States v. Miller, 425 U.S. 435 (1976); Smith v. Maryland, 442 U.S. 735 (1979).
 Miller, 425 U.S. at 442.
 Smith, 442 U.S. at 746.
 Katz, 389 U.S. 347.
 United States v. Knotts, 460 U.S. 276 (1983) and United States v. Karo, 468 U.S. 705 (1984).
 United States v. Knotts, 460 U.S. at 281; see Rakas v. Illinois, 439 U.S. 128, 153-54 (1978) (Powell, J., concurring).
 Id. at 276.
 Id. at 279.
 Id. at 285.
 Id. at 281.
 Id. at 283.
 Knotts, 460 U.S. at 284.
 Karo, 468 U.S. at 713.
 Id. at 714.
 See Riley v. California, 134 S.Ct. 2473 (2014); Jones, 565 U.S. 400.
 Riley, 134 S.Ct. at 2485.
 Chimel v. California, 395 U.S. 752 (1969).
 United States v. Robinson, 414 U.S. 218 (1973).
 Riley, 134 S.Ct. at 2485.
 United States v. Jones, 565 U.S. at 404.
 Id. (The government had applied for the warrant, but the 10-day period in which to execute it had expired, and when officers placed the GPS on the vehicle, it was in Maryland, not Washington, D.C., as the warrant prescribed.)
 Id. at 403.
 Id. at 411 (Five justices decided the case on the basis of trespass, and four justices felt the expectation of privacy definition of a search was more applicable here. One justice stated that both standards could apply, but chose to side with the majority on the narrower ground of trespass.)
 Riley, 134 S.Ct. 2473; Jones, 565 U.S. 400.
 Spencer S. Hsu, Court: Warrantless requests to track cellphones, Internet use grew sevenfold in D.C. in three years, THE WASHINGTON POST (July 18, 2017) https://www.washingtonpost.com/local/public-safety/court-warrantless -requests-to-track-cellphones-internet-use-grew-sevenfold-in-dc-in-three-years/2017/07/18/b284ac32-6b36-11e7-9c15-177740635e83_story.html?utm_term=.0d4a43b08636
 Eric Lode, Validity of Use of Cellular Telephone or Tower to Track Prospective, Real Time, or Historical Position of Possessor of Phone Under Fourth Amendment, 92 A.L.R. Fed. 2d 1, *2 (2015).
 Stored Communications Act, 18 U.S.C. §§ 2701, et seq. (2017)
 United States v. Graham, 824 F.3d 421 (4th Cir. 2016); In re United States for Historical Cell Site Data, 724 F.3d 600 (5th Cir. 2013); United States v. Davis, 785 F.3d 498 (11th Cir. 2015) )(cert. Denied 136 S.Ct. 479 (2015).
 In re Application of United States for an Order Directing a Provider of Elec. Commun. Serv. to Disclose Records to Gov’t, 620 F.3d 304 (3rd Cir. 2010).
 Id. at 315.
 Id. at 317.
 Historical Cell Site Data, 724 F.3d at 613.
 Id. at 608.
 Id. at 615.
 Davis, 785 F.3d 498.
 Id. at 501.
 Id. at 507.
 Graham, 824 F.3d at 424.
 Id. at 430.
 David LaBahn, Symposium: A Defense of the Doctrine, SCOTUSBLOG (Aug. 2, 2017), http://www.scotusblog.com/2017/08/symposium-defense-doctrine/
 Knotts, 460 U.S. at 284.
 See United States v. Skinner, 690 F.3d 772, 778 (6th Cir. 2012) and Knotts, 460 U.S. at 284.
 Jones, 565 U.S. at 429 (Alito, J., concurring in the judgment).
 Financial Right to Privacy Act
 18 U.S.C. § 2703(d) (2017).
 See, e.g. Graham, 824 F.3d at 441; Davis, 785 F.3d at 521.
 See Elec. Commun. Serv. to Disclose Records to Gov’t, 620 F.3d 304; Graham, 824 F.3d 421; Historical Cell Site Data, 724 F.3d 600; Davis, 785 F.3d 498.
 Graham, 824 F.3d at 438; Davis, 785 F.3d at 519, 524; Elec. Commun. Serv. to Disclose Records to Gov’t. 620 F.3d at 319.
 Graham, 824 F.3d at 441; Davis at 521
 Davis, 785 F.3d at 533; Historical Cell Site Data, 724 F.3d at 615.
 Jones v. United States, 168 A.3d 703 (D.C. 2017).
 Id. at 709.
 Id. at 713.
 Davis, 785 F.3d at 525.
 Miller, 425 U.S. at 451.
 Smith, 442 U.S. at 748 (dissent joined by Brennan, J.).
 See United States v. Warshak, 631 F.3d 266 (6th Cir. 2010); Ferguson v. City of Charleston, 532 U.S. 67 (2001) (holding that a hospital patient retains a reasonable expectation of privacy in diagnostic tests and can expect that the test results will not be shared with nonmedical personnel without patient’s consent); Bond v. United States, 529 U.S. 334 (2000) (holding that a bus passenger has a protected privacy interest in luggage even though he might expect that a bus employee might handle it in a non-exploratory manner).
 Warshak, 631 F.3d at 288.
 Stored Communications Act, 18 U.S.C. § 2703(b) (2017) (allowing governmental entities to require a provider of remote computing services to disclose the contents of wire or electronic communications without a warrant or a showing of probable cause).
 Warshak, 631 F.3d at 288.
 Id. at 412.
 United States v. Jones, 565 U.S. at 404.
 Id. at 411.
 Id. at 418.
 Id. at 413-14.
 Id. at 414
 Id. at 417.
 Id. at 417.
 United States v Carpenter, 819 F.3d 880 (6th Cir. 2016) (cert. granted 137 S.Ct. 2211, June 5, 2017).
 All speculation regarding how the Court may decide the case is based on pleadings submitted at the time of writing and a transcript of the oral arguments in this case.
 Carpenter, 819 F.3d at 884.
 Carpenter, 819 F.3d at 883-84.
 United States v. Carpenter Oral Arg. 3:22-25, 4:9-13, Nov. 29, 2017.
 Riley, 134 S.Ct. 2473.
 Carpenter, 819 F.3d 880.
 United States v. Carpenter Oral Arg. 24:9-13, Nov. 29, 2017.
 Id. at 24:14-18.
 Id. at 6:20-25.
 Id. at 51:6-12.
 Id. at 4:16-24 (citing Miller, 425 U.S. at 442).
 Riley, 134 S.Ct. 2473; Jones, 565 U.S. 400.
 United States v. Robinson, 414 U.S. 218 (1973) (The Robinson case introduced the “container” doctrine, which allows law enforcement officers to search any containers found on an arrestee’s person for weapons or evidence of the crime of arrest, citing an interest in officer safety. Lower courts applied this doctrine liberally, and the Supreme Court has since had to narrow the doctrine’s application in United States v. Chadwick, 433 U.S. 1 (1977) and Arizona v. Gant, 556 U.S. 332 (2008). The Court ruled that cell phones were not “containers” that could be searched under this doctrine in 2014 in Riley.).
 See Jim Harper, Symposium: Granular Analysis Versus Doctrine in Carpenter, SCOTUSBLOG (Aug. 1, 2017), http://www.scotusblog.com/2017/08/symposium-granular-analysis-versus-doctrine-carpenter/
 Chimel v. California, 395 U.S. 752 (1969).
 Cindy Cohn, Protecting the Fourth Amendment in the Information Age: A Response to Robert Litt, Electronic Frontier Foundation 126 Yale L.J. F. 107 (2016).
 18 U.S.C. § 2703 (2017).
 Id. at § 2703(d).