– The Supreme Court on Tuesday threw out a broad lawsuit that challenged the constitutionality of the government's program of secret wiretapping of international phone calls and e-mails, ruling that none of the plaintiffs has "standing" to sue because they cannot prove their messages were intercepted.

The decision, by a 5-4 vote that divided along ideological lines, probably means the Supreme Court will never rule on the constitutionality of that 2008 law.

More broadly, the ruling illustrated how difficult it is to mount court challenges to a wide array of anti-terrorism measures, including renditions of terrorism suspects to foreign countries and targeted killings using drones, in light of the combination of government secrecy and judicial doctrines limiting access to the courts.

"Absent a radical sea change from the courts, or more likely intervention from the Congress, the coffin is slamming shut on the ability of private citizens and civil liberties groups to challenge government counterterrorism policies, with the possible exception of Guantanamo," said Stephen Vladeck, a law professor at American University.

The challenges to the programs of secret surveillance floundered from the start because no one can show they were targeted or that their calls were intercepted. Civil libertarians have described this as a Catch-22, because the government will not reveal information on whose calls and messages have been intercepted.

Justice Samuel Alito Jr., speaking for the court's conservative majority, said the latest lawsuit fails because it was based on "speculation" by lawyers, journalists and activists who feared their messages were being intercepted by the National Security Agency.

The plaintiffs argued that because they had clients abroad and had regular dealings with them, their messages were probably intercepted by the NSA. They argued this policy of intercepting private calls violated the Fourth Amendment's ban on unreasonable searches.

In dissent, the court's four liberal justices said the suit should have proceeded because the plaintiffs had to alter their work practices to avoid having their confidential calls overheard. "In my view, this harm is not 'speculative,' " said Justice Stephen Breyer.

The New York Times contributed to this report.