When the government sets its sights on gaining a new, technologically-enabled ability to keep better tabs on suspected bad guys, they just don't take "no" for an answer. They also apparently don't take "yes, but with strict oversight" for an answer either.

Since October of this year the US Department of Justice has tried four times in four different venues to get the courts to grant them the ability to force cell phone providers to turn over real-time, continuous physical location data on cell phone users, without first having to obtain a warrant or even demonstrate probable cause. Three times, the DoJ's request was smacked down by the courts in harshly written opinions, but the fourth time was a charm for the DoJ.

This past Tuesday, a federal judge in New York ruled that the federal government is free to track citizens' physical locations via their cell phones under a much more lenient legal standard than probable cause. Unlike the NSA wiretapping case, this doesn't mean that the feds don't have to notify the courts at all, but it does mean that they don't have to be able to prove probable cause in order to get the courts to grant a tracking request.

I'm not by any means versed on the legal issues here, but this blog entry by Daniel J. Weitzner at MIT's Decentralized Information Group has the clearest explanation that I've seen on what's going on here. The entry was written after the first three requests had been denied but before Tuesday's ruling:

The key legal issue in all of these cases is what level of judicial oversight is required to compel the disclosure of information sought by the government. Answering this question has turned on whether the data sought is "transactional information" generated by the mobile phone network (in which case it would be regulated under 18 USC 2703 sections (b) and (d)) or that it is equivalent to a mobile tracking device regulated under 18 USC 3117? If it is transactional data then it is available to the government under a so-called intermediate standard, less than probably cause, but more than a simple request. Under this rule, the government has to give a clear and articulable reason which the data is relevant to an ongoing investigation. It can't just be going on a fishing expedition. Though the government advocated this position is all three cases, all three courts found that there must be a showing of probable cause. (This is all personally pretty interesting to me because I did a lot of work advocating for this new protection for transactional data back in 1994. At the time we (and I believe the Congress) was thinking about transactional information such as email and web access logs. We were not thinking about real time location data. My guess is that Congress will have to come back to this question to settle it.

So the primary issue here is not whether the government can track your location via cell phonethey definitely can get at cell phone location data, and they've had that ability for a whilebut just how much judicial oversight will be required of the feds in exercising this power. The answer, as of today, is "not much."

On my very brief and non-expert reading of the opinion, it appears that the judge has ruled that cell phone location data is indeed a form of "transactional information," government access to which is regulated under 18 USC 2703 (in combination with a few other statutes), and is therefore available to the government under a more lenient standard than probable cause. From page 21 of the ruling:

...The text of section 2703(c) covers the data the Government seeks here. The heart of the statute ? granting authority to obtain "information" about cell phone customers ? does not on its face contain any limitation regarding when such information may come into being. It is thus susceptible to an interpretation that the "information" sought might come into being in the future. Moreover, because cell site data in this District exists as a record before it is transmitted to the Government, the text of the statute does not prevent the Government from presenting daily or hourly (or even more frequent) applications to the Court to obtain historical cell site data. Thus, as a theoretical matter, the statute permits the Government to obtain cell site data on a continuing or ongoing basis even under a narrow reading of section 2703.

Unlike the EFF, which is outraged by this ruling, I'm inclined to look on the bright side: minimal, token judicial oversight of law enforcement domestic surveillance activities is always better than none at all.