A U.S. terrorism defendant who was formally notified that he was spied on by the NSA filed a challenge to the constitutionality of the surveillance today, in a case likely to be litigated all the way to the Supreme Court.

Jamshid Muhtorov, a native of Uzbekistan who immigrated to Colorado, is one of only two criminal defendants the government has conceded was charged on the basis of evidence scooped up by the NSA's surveillance programs. The spying was authorized by the controversial FISA Amendments Act.

The Supreme Court last year rejected a suit challenging the law because the civil rights groups and others who brought the case could not prove their communications were intercepted, and hence didn't have "standing" to sue. That issue won't come up for Muhtorov, says the Americans Civil Liberties Union, which is representing Muhtorov.

"For five years the government insulated this statute from judicial review by concealing from criminal defendants how the evidence against them was obtained," says Mark Silverstein, legal director of the ACLU's Colorado chapter. "But the government will not be able to shield the statute from review in this case."

Following a new Justice Department policy, the U.S. told Muhtorov several months ago that it intended to submit evidence from "information obtained or derived from acquisition of foreign intelligence information conducted pursuant" to the FISA law, known as the FAA.

"Mr. Murhtorov now moves to suppress the fruits of the FAA surveillance on the grounds that the government’s monitoring of his communications under the statute violated the Fourth Amendment of the U.S. Constitution," according to his 69-page motion today in a Colorado federal court.

The authorities have not disclosed the evidence at issue, but they maintain that Murhtorov communicated overseas with a terror group known as Islamic Jihad Union, allegedly discussing his willingness to become a martyr. He is charged with conspiring to provide material support to that group in Uzbekistan.

Until the recent policy change, the Obama administration had never divulged to a single defendant that they were the target of warrantless phone or email surveillance under the FAA.

Rights advocates suspected the federal prosecutors were keeping mum — and perhaps violating federal rules requiring the government to tell defendants where evidence was obtained — because such a concession would pave the way for a challenge to the constitutionality of the surveillance tactics, which Congress approved in 2008 and then again over a year ago.

Today’s challenge comes months after U.S. Solicitor General Donald Verrilli Jr. was reportedly arguing internally at the Justice Department that there was "no legal basis" for failing to disclose to defendants if they were a target of the warrantless surveillance.

While only two defendants have been notified — the other an Oregon man accused of trying to blow up a Portland tree lighting ceremony — there are likely plenty of defendants ensnared under the program.

In Senate hearings in December 2012, just days before the legislation was set to expire, Sen. Dianne Feinstein (D-California) successfully urged her fellow lawmakers to do what the House had done: Reauthorize the act for another five years. She described at least nine terror plots that were broken up by the program, and said, "There have been 100 arrests to prevent something from happening in the United States; some of these plots have been thwarted because of this program. I think it is a vital program." (.pdf)

The government’s secrecy on the matter was pivotal in killing a legal challenge to the legislation before the Supreme Court.

When the Supreme Court last year set aside a challenge on a 5-4 vote, the justices said that if the government "intends to use" evidence obtained without a warrant under the law, "the government must provide advance notice of its intent, and the affected person may challenge the lawfulness of the acquisition."

The act generally requires the Foreign Intelligence Surveillance Court to rubberstamp terror-related electronic surveillance requests. The government does not have to identify the terrorism target or facility to be monitored. It can begin surveillance a week before making the request, and the surveillance can continue during the appeals process if, in a rare case, the secret FISA court rejects the surveillance application. The original target of the surveillance must be believed to be outside the United States.