Defence lawyers in several terrorism cases in the United States are planning to appeal against the convictions of their clients on the ground that evidence may have been garnered from illegal wiretapping by a federal government surveillance agency.
The threat is the latest repercussion of the disclosure two weeks ago that the Bush administration had used the National Security Agency (NSA) - supposed to go after foreign targets - to conduct electronic surveillance without warrants inside the US, and against American citizens.
Among the cases is that of Ali al-Timimi, a Muslim scholar, who is serving a life sentence for involvement with an alleged "Virginia jihad" cell, and for inciting his students to wage war overseas against the US.
Edward McMahon, Timimi's lawyer, told The New York Times he always had doubts about the explanation offered by federal investigators of how they came to suspect his client of links with terrorism. "The case against a lot of these guys just came out of nowhere because they were really nobodies. It makes you wonder whether they were being tapped."
The focus of the appeals would be on whether prosecutors misled the courts about the source of some evidence, and whether the authorities held back other NSA wiretaps suggesting that individuals charged might be innocent.
The NSA programme was revealed by The New York Times. Opponents said it was a blatant violation of civil liberties, but the White House insisted it was an essential tool in the fight against terrorism.
President George Bush has defended the wiretaps and said that the leak concerning their use was "shameful".
The debate is set to continue in the new year - assuming that Arlen Specter, the Pennsylvania Republican who heads the Senate Judiciary Committee, goes ahead with his threat to hold hearings on the eavesdropping when Congress reconvenes next month.
Not only Democrats but several senior Republicans have expressed unease at the way the NSA has been used to bypass a federal court set up in 1978 to authorise warrants for clandestine wiretaps. One of the court's 10 judges resigned in protest, while its chief has demanded a full briefing from the administration on why it had been cut out of the process.
The affair has complicated Bush administration efforts to extend the Patriot Act, the anti-terror law passed by Congress in the wake of the 9/11 attacks. Key provisions of the Act that were to expire at the end of 2005 have been granted only a one-month extension, despite angry complaints from Mr Bush.
The White House maintains that speed is of the essence in combating terrorism, and that NSA domestic surveillance had been sparingly used. It was "designed to monitor calls from very bad people to very bad people," an official told The New York Times.
But for many Americans, the very notion of intelligence agencies eavesdropping on domestic targets raises the spectre of Watergate, "dirty tricks," and how Richard Nixon used the CIA to snoop on his political opponents.
There are also profound constitutional implications. Many experts see the episode as more proof of how Mr Bush, urged on by Vice-President Dick Cheney, is relentlessly expanding the power of the executive, freeing it from the fetters of Congress. For that reason, reopening the cases could be very difficult, some analysts say - even in cases where mistakes have been made.
The victim of one such error was Brandon Mayfield, an Oregon lawyer who was wrongly arrested in connection with the March 2004 Madrid train bombings before being released. Mr Mayfield is now suing the government and is likely to raise the NSA wiretapping issue.
Meanwhile, the independent watchdog body that oversees the CIA is investigating up to 10 cases where suspected terrorists may have been handed over in error by the agency to foreign governments, under the contested "rendition" programme. The practice pre-dates 11 September 2001, but after the attacks on New York and Washington, President Bush gave the CIA authority to act without case-by-case approval by the government. Some 100 to 150 people have been targets, either arrested in the US or snatched from the streets of a foreign city and handed back to their home country for questioning - frequently, it is said, for torture.Reuse content