Losing Track of the Tracking Device Statute

You, a first-year law student taking your Crim Pro exam, quickly scan the first question: “Can a cell phone be a tracking device?” Your initial reaction – must be a trick question, right? Everybody knows that snitch in your purse faithfully follows you wherever you go. But you’ve been around law school long enough to know that what’s true in fact may not be true as a matter of law. So you check the statutory definition of ‘tracking device’ helpfully reprinted down the page:

“an electronic or mechanical device which permits the tracking of the movement of a person or object.” 

No tricky ambiguity there. Your smartphone is certainly an ‘electronic device’ that ‘permits’ the tracking of a ‘person’ (you). Check the ‘yes’ box, and move on. Easy peasy, right?

Not according to the 1st Circuit Court of Appeals. In United States v. Ackies,  currently the subject of a pending cert petition at the Supreme Court, the court found that the federal Tracking Device Statute does not apply to cell phones.[1] This series of posts will explain the strange path taken by the court to arrive at this wrong destination, and why the Supreme Court should take the case and correct the error.


The modern cell phone is a multi-functional marvel. As the Chief Justice has written, these devices “are in fact minicomputers that also have the capacity to be used as a telephone.”[2] From the perspective of law enforcement, perhaps its most useful capacity is location tracking. Cell phones have been called ‘the world’s most effective tracking devices,”[3] and the Supreme Court has explained why: cell phones have become almost a “feature of human anatomy,” compulsively carried all the time, even in the shower; so that “when the Government tracks the location of a cell phone, it achieves near perfect surveillance, as if it had attached an ankle monitor to the phone’s user.”[4]

With all eyes on Carpenter’s resolution of the Fourth Amendment issue, little attention has been paid to the statutory regulation of tracking devices which began in 1986. Part of comprehensive legislation known as the ECPA, the Tracking Device Statute (TDS) is easy to overlook, occupying a single section of the U.S. Code, 18 U.S.C. 3117. It has two parts: the straightforward definition of “tracking device” in 3117(b), set out above, and the following venue provision in 3117(a):

If a court is empowered to issue a warrant or other order for the installation of a mobile tracking device, such order may authorize the use of that device within the jurisdiction of the court, and outside of that jurisdiction if the device is installed in that jurisdiction.

[5]In 2006, Congress approved Rule 41 amendments fleshing out more detailed procedures for tracking warrants. These  include a probable cause standard, a 10-day installation period, a 45-day monitoring period, as well as return and notice requirements.[6]

Significantly, the new rule adopted the same broad definition of tracking device enacted by Congress two decades earlier. Despite remarkable advances in tracking technology after 1986 – GPS first became available for civilian use in the late 1990s – there was no need to alter this definition. Congress had the foresight in 1986 to adopt a “technology-neutral” definition that would not soon be rendered obsolete by advances in tracking technology.

The breadth of the definition was commented upon in ECPA legislative hearings.  According to the executive vice president of a major mobile communications company, the definition “is broad enough that it could be read as including paging and cellular equipment.”[7] Even so, the definition remained unchanged throughout the drafting process. Prior to the 2006 rule amendments, several magistrate judges had held that a cell phone becomes a tracking device, in fact and in law, when used to monitor its user’s location in real time. Since that time, a majority of lower courts have agreed, and no appellate courts had weighed in. Until this year.


Carey Ackies was convicted of drug trafficking based in part on evidence derived from two “precise location information” warrants, issued by a magistrate judge sitting in Maine, authorizing GPS tracking of his cell phone in New York. Ackies challenged the PLI warrant on jurisdictional grounds, claiming that such out-of-state monitoring was improper under the venue provisions of the TDS. The government argued (1) that the TDS did not apply to cell phones, and (2) that the warrant was authorized by a different law, the Stored Communications Act (SCA), which has a much broader jurisdictional reach than  TDS.

The appellate court agreed with the government on both counts. Let’s examine its rationale for the TDS holding first.


Statutory interpretation begins, and often ends, with the text of the statute. The First Circuit correctly cited the general rule: “When the statute’s language is plain, the sole function of the courts – at least where the disposition required by the text is not absurd – is to enforce it according to its terms.”[8] However, a stricter corollary of the plain meaning rule applies to statutory definitions: “When a statute includes an explicit definition, we must follow that definition, even if it varies from the term’s ordinary meaning.” Stenberg v. Carhart, 530 U.S. 914, 942 (2000). In other words, courts have less leeway than usual in construing the ‘plain meaning’ of words which Congress has expressly defined in the statute.

But the Ackies court gave no special deference to the plain meaning of ‘tracking device’ in 3117(b).  Instead, the court zeroed in on two words in a phrase -- “installation of a mobile tracking device”-- appearing in the venue section of the statute. The court argued that the plain meaning of those two words necessarily excluded the cell phone as a tracking device for purposes of the TDS, and so a literal reading of 3117(b) would lead to an absurd result.

The problem with the court’s argument is that its chosen meanings for the terms “installation” and “device” are not so plain. In both cases the court has cherry-picked permissible restrictive meanings, while arbitrarily ruling out more inclusive meanings that would avoid absurdity.  According to the court, the plain meaning of ‘installation’ refers to the physical placement of some hardware or equipment.[9] But in common usage ‘installation’ need not involve just tangible objects (think washing machines); just as frequently it involves non-tangible things (think software). After you download any app on your phone, what do you do next? Click “INSTALL”, and it is then ready for later use.

Attempting to rebut the software counterexample, the court declared that software is not a ‘device’, because the plain meaning of that word is a “piece of equipment” like hardware.[10] Once again, this is an arbitrarily narrow interpretation. Electronic devices like computers consist of both hardware and software. Complete installation of any digital device –such as a modern-day GPS tracking device—requires installing both the physical hardware and the necessary software to tell the hardware what to do.[11]

A recent personal experience makes the point. My wireless printer recently conked out, requiring a trip to the store to replace the device. I took the new printer out of the box, placed it on my credenza, plugged it in – and nothing. Despite my best efforts, the printer did not function – its display read “no connection to wireless network.” A call to the Geek Squad resolved the problem, after they remotely installed the proper software to make the required connection. Until then, my printer may have been physically installed by my desk, but it was still a useless box of plastic, glass, and wires.

According to various standard dictionaries, a primary meaning of the verb ‘install’ is “to set up for use or service.”[12] This is a perfectly apt description of my wireless printer installation, as well as the installation of Mr. Ackies’ tracking device. In both cases, the device has already been physically placed in position by the user. The only task remaining to complete the set-up was to configure the software to enable printing or monitoring, as the case may be.

To be sure, standard dictionaries do not exclude the narrow, restrictive uses of the words ‘installation’ and ‘device’ favored by the Ackies court. ‘Installation’ can include physical placement via alligator clips, and ‘device’ can include non-digital devices like a mouse trap. But it does not follow that those examples are exhaustive. Such reasoning commits the basic logical fallacy of composition—the duck in my yard is white, therefore all ducks are white.

The court’s restrictive reading of 3117(a) seems deliberately intended to clash with the broad statutory definition of 3117(b). It’s as if a delivery truck driver chose to stay parked in the one freeway lane blocked by a stalled vehicle, while traffic in other lanes flowed freely. A cardinal rule of statutory construction is to interpret one section in harmony with all the others, wherever possible.[13] Rather than steer around the conflict, the court aimed straight for it.


Apart from the dictionary, the court posed two weak consequential rationales for remaining in the stalled lane.  The first was the alleged difficulty of determining where the installation of digital tracking devices occurs for purposes of the venue restriction in 3117(a).There is a common-sense answer to this – installation occurs wherever the device is located when set up is complete, that is, when both hardware and software are in place.  In Ackies’ case, the installation took place in New York, where the cell phone was located when ATT did the necessary keystrokes to enable its use as a tracking device by law enforcement. Nothing particularly difficult about that. 

The second proffered rationale is just as feeble: sometimes the present location of the cell phone is unknown, so the venue restriction may be difficult to satisfy on occasion.  To the extent this is a real problem (my experience in granting dozens of cell phone TDS warrants suggests not), the ready response is that Rule 41 has several venue restrictions that are sometimes problematic for law enforcement. But surely this is a policy matter for Congress, not an excuse for courts to disregard unambiguous definitions in the U.S. Code.


The particular mode of installation is immaterial to the simple, functional definition of ‘tracking device’ enacted by Congress. If it walks like a duck, swims like a duck, and quacks like a duck, it’s a duck. As Monty Python would say, “The plumage don’t enter into it.”

The Ackies decision transmutes the TDS from a capacious, forward-looking, technology-neutral statute into its opposite – a hidebound anachronism applicable only to 1980s-vintage non-digital transponders surreptitiously installed by alligator clip. With all due respect, this is statutory invention, not statutory interpretation.

Next time: “Why Are Precise Location Warrants a Thing?”

[1] U.S. v. Ackies, 918 F.3d 190 (1st Cir. 2019), cert. pending, Case No. 19-6602 (filed 11/13/19). 

[2] Riley v. California, 573 U.S. 373, 393 (2014).

[3] Julia Angwin, Dragnet Nation 141 (2014).

[4] Carpenter v. U.S., 138 S. Ct. 2206, 2218 (2018).

[5] See e.g. 396 F.Supp.2d 747, 354 (S.D. Tex. 2005); 396 F.Supp.2d 294, 311 (E.D.N.Y. 2005).

[7] See In re Application for Order Authorizing Prospective and Continuous Release of Cell Site Location Records, 31 F. Supp. 889, 898 n. 44 (S.D. Tex. 2014), citing  Statement of John Stanton, Hearing on H.R. 3378, The Electronic Communications Privacy Act before the Subcommittee on Courts, Civil Liberties and the Administration of Justice, House Judiciary Committee, Oct. 24, 1985.

[8] 918 F.3d at 201, quoting Hartford Underwriters Ins. Co. v. Union Planters Bank, N.A., 530 U.S. 1, 6 (2000).

[9] Id. at 199.

[10] Id. at n. 5.

[12] See https://www.merriam-webster.com/dictionary/install ; https://www.vocabulary.com/dictionary/install (“to set up for use”); see also https://www.dictionary.com/browse/install (“to place in position or connect for service or use”).

[13] Food and Drug Admin. v. Brown & Williamson Tobacco Corp., 529 U.S. 120, 133 (2000).


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