Roughly a year and a half since the first Snowden disclosures, there's already been a judicial order to shut down the National Security Agency's bulk metadata collection program.

The lawsuit filed by Larry Klayman, a veteran conservative activist, would essentially put a stop to unchecked NSA surveillance. And at the start of 2015, he remains the only plaintiff whose case has won when fighting for privacy against the newly understood government monitoring. However, it's currently a victory in name only—the judicial order in Klayman was stayed pending the government’s appeal.

Klayman v. Obama is only one of a number of notable national security and surveillance-related civil and criminal cases stemming fully or partially from the Snowden documents. In 2014, a handful of these advanced far enough through the legal system that 2015 is likely to be a big year for privacy policy. One or more could even end up before the Supreme Court.

"I think it's impossible to tell which case will be the one that does it, but I believe that, ultimately, the Supreme Court will have to step in and decide the constitutionality of some of the NSA's practices," Mark Rumold, an attorney with the Electronic Frontier Foundation, told Ars.

Rumold is one of the attorneys in First Unitarian Church, a case that is challenging government surveillance much like Klayman. Along with that pair, headline watchers should set alerts for cases such as American Civil Liberties Union (ACLU) v. Clapper, United States v. Moalin, and United States v. Muhtorov. Not only are there several other related cases that will likely be influenced by these decisions, but those five cases represent the strongest and most direct legal challenges to the current NSA surveillance state.

Ain't no party like a third party!

Before outlining the relevant cases, it's important to note the government's general justification for the legality of bulk metadata collection: the third-party doctrine.

This theory was codified most recently from a 1979 Supreme Court decision in Smith v. Maryland. In the case, the court found that individuals do not have an inherent privacy right to data that has already been disclosed to a third party. So with telecom data for instance, the government has posited that because a call from one person to another forcibly transits Verizon’s network, those two parties have already shared that data with Verizon. Therefore, the government argues, such data can't be private, and it’s OK to collect it.

But legal experts say that recent surveillance and privacy Supreme Court decisions could lead the courts to reconsider. The first Snowden revelation (published in June 2013) was that Verizon (and presumably other telecom firms) are routinely handing over all call records to the NSA. The metadata records include the date, times, and lengths of the calls.

In October 2013, the third-party doctrine was upheld. A Foreign Intelligence Surveillance Act Court (FISA Court) judge ruled that there was no privacy interest in such metadata collected and analyzed by the NSA. In short, if it's OK to collect third-party data on one person, it's OK to collect it on a bunch of people.

Put another way, where one individual does not have a Fourth Amendment interest, grouping together a large number of similarly situated individuals cannot result in a Fourth Amendment interest springing into existence ex nihilo. In sum, because the Application at issue here concerns only the production of call detail records or "telephony metadata" belonging to a telephone company, and not the contents of communications, Smith v. Maryland compels the conclusion that there is no Fourth Amendment impediment to the collection. Furthermore, for the reasons stated in—and discussed above, this Court finds that the volume of records being acquired does not alter this conclusion. Indeed, there is no legal basis for this Court to find otherwise.

Further Reading Cops must have a warrant to search cell phones, rules Supreme Court

But consider two recent Supreme Court cases: United States v. Jones (2012) and Riley v. California (2014). Both were decided by rare unanimous opinions, and both indicate an awareness that modern tech has changed reasonable privacy. Jones determined that law enforcement does not have the authority to place a GPS tracker on a suspect without a warrant. Meanwhile, the court found in Riley that law enforcement cannot search a person’s phone incident to arrest without a warrant.

"[These cases] are strong signs that the Supreme Court is aware that rules that were created in a period of time when the court analyzed targeted surveillance do not blindly apply where the government is collecting huge quantities of information," Patrick Toomey, an attorney with the American Civil Liberties Union, told Ars.

"As the quantity expand, a new constitutional analysis arises. We think the same type of principle applies here. Smith v. Maryland is one suspect’s data over three days as opposed to the information contained in everyone’s call records contained for 10 years or more."

For his part, the EFF's Rumold agreed with this reasoning.

"Riley signals that the Supreme Court recognizes that technological distinctions matter, and we can't blindly apply old precedent to new technology," he added. "Jones, or at least the concurrences in Jones, signal that the scope and duration of surveillance makes a difference for constitutional purposes. Those twin principles put much of the NSA's domestic spying programs on pretty unsound constitutional footing."

Listing image by Oliver Wunder remixed by Aurich Lawson