The U.S. government insists that Americans don’t have the right to challenge a law that lets the National Security Agency eavesdrop on the intimate communications of anyone in the country, but all of that could now change as early as this week.

The Supreme Court will officially start their second session of the year on Monday, and first on the agenda is a matter that could eventually shatter the government’s ability to order wiretaps on the emails and phones of any U.S. citizen without ever obtaining a warrant.

The Foreign Intelligence Surveillance Act (FISA) was put into place in the 1970s to install safeguards to keep Americans safe from unlawful eavesdropping. But following the terrorist attacks of September 11, the George W. Bush administration ordered amendments to the law that have ever since allowed the NSA to monitor the communications of any U.S. citizen as long as the government suspects that they are corresponding with anyone outside of the country.

Last month, the House of Representatives voted to reauthorize the 2008 FISA Amendment Act (FAA), but not without attracting criticism from some very concerned parties. The American Civil Liberties Union filed a legal brief warning, “Under the FAA, the government can target anyone — human rights researchers, academics, attorneys, political activists, journalists — simply because they are foreigners outside the United States, and in the course of its surveillance it can collect Americans’ communications with those individuals.”

Beside from the obvious opposition to the warrantless wiretapping of any American with no explanation, there’s another problem that has put the FAA in the spotlight. The Justice Department has insisted that Americans can’t challenge the eavesdropping provisions because no civilians can say with absolute certainty that they have been targeted by secret surveillance.

The reason Americans can’t prove they’ve been monitored, of course, is because the government won’t give them yes or no answer anytime they’ve been asked.

Each time the question comes up over who has been targeted, the government has defaulted to say that national security prohibits them from disclosing who’s been subjected to NSA spying, claiming state secret privilege to prevent disclosing even the bare bones of their wiretapping program. When two U.S. senators asked the Office of the Inspector General of the Intelligence Community earlier this year, “how many people inside the United States have had their communications collected or reviewed under the authorities granted by section 702” of the FAA, the NSA fired back by saying even responding to that inquiry would be against their rules.

A “review of the sort suggested would itself violate the privacy of U.S. persons,” Inspector General I. Charles McCullough wrote, adding that the request would be “beyond the capacity” of his office and that “dedicating sufficient additional resources would likely impede the NSA’s mission.”

“The overwhelming power of the state secrets privilege makes it nearly impossible for any U.S. citizen to show that he or she was the subject of surveillance, while the inability to prove he or she has been spied on prevents any citizen from having standing to challenge the program,” Frank Matt explained for the Arab American Institute.

But although the NSA won’t come close to offering any details, the texts of the FISA amendments open up literally any American citizen to government surveillance as long as their emails, phone calls or instant messages are sent to someone abroad, whether it’s a cousin in Canada or an employee working overseas.

“Rather than target its surveillance power at a specific person thought to be the agent of a foreign power, the government can target its surveillance power at a group of people, a neighborhood, a country or a geographic region,” the ACLU insists.

Rep. Dennis Kucinich (D-Ohio) argued on the Hill last month against reauthorizing the FAA, telling his colleagues in Congress, “Everyone becomes suspect when big brother is listening.” Now before any Americans can try to say that the surveillance allowed under those 2008 amendments violate the US Constitution, they need to convince the court that they should be able to bring the matter up.

On Monday, the Supreme Court will hear oral arguments regarding Clapper v. Amnesty International, a case being fought to show that opponents of the FAA have a right to bring their suit up in Washington. Those that call the warrantless wiretapping illegal will have a hard case to fight, though, given that they can’t prove they’ve been watched.

“Unfortunately, the government has tried to block the courts from ever reaching that constitutional issue, arguing that unless the plaintiffs can prove they will be monitored (which is impossible, since the list of who is monitored is classified), they cannot sue,” former NSA agents-turned-whistleblowers Bill Binney and J. Kirk Wiebe write in a recent op-ed in Politico.

The US Second Circuit has already ruled in Clapper that the plaintiffs — attorneys, journalists and activists from human rights organizations — should be able to challenge the constitutionally of those amendments. Because those parties cannot prove that they’ve been personally subjected to the surveillance, though, it has been an uphill battle all the while.

The Brennan Center for Justice out of the New York University Law School notes, “given the nature of their professional work,” the Second Circuit previously ruled that the plaintiffs had “a reasonable fear that they were in fact subject to such surveillance and had to take costly steps to protect the confidentiality of their communications.” That’s enough, they say, to show that the plaintiffs “satisfied the required showing of a concrete injury resulting from the challenged amendments sufficient to establish standing to sue and reversed the contrary finding of the district court.”

“Because the identity of persons subject to surveillance is a government secret, it is highly unlikely that any U.S. persons could ever show that they were in fact the subject of such surveillance. Accordingly, if the plaintiffs-respondents in this case do not have standing, it is likely that serious questions as to whether surveillance conducted under the 2008 amendments violate the First and Fourth Amendments will escape review altogether,” the center adds.

On their part, the ACLU agrees that the plaintiffs have good reason to believe that they’ve been monitored under the 2008 amendments. “Some plaintiffs communicate with people who have been the targets of surveillance or other U.S. government attention in the past,” the ACLU wrote in last month’s brief, specifically bringing up clients whose jobs require them to, for example, communicate with indigenous rights advocates in Columbia, or corresponds with former CIA detainees for human rights research.

The ACLU adds that an appeals court panel already agreed in 2011 that “plaintiffs have good reason to believe that their communications, in particular, will fall within the scope of the broad surveillance that they can assume the government will conduct,” and the US Court of Appeals for the Second Circuit later refused the government’s attempts to reverse that decision. Now if the Supreme Court can come to the same conclusion, those plaintiffs — the ones who may or may not have ever been surveilled — can finally challenge the constitutionality of the FISA amendments.

“While it may seem like a minor step in the battle against the abuses of FISA, the outcome of this case could have profound implications for future civil liberties cases,” Frank Matt adds in his article this week. equating the government’s defense of the FAA as “Kafkaesque resistance.”

“Based on our combined six-plus decades of experience working at the NSA, we are sure there is only one just outcome,” Binney and Wiebe write to Politico. “The justices should let this case proceed, giving the courts the opportunity to determine whether the executive and legislative branches have gone too far.”

“The NSA cannot be trusted with this power. No agency should be.”