The Sixth Circuit Court of Appeals Friday rejected a legal challenge by the American Civil Liberties Union to the Bush administration's warrantless surveillance program by a margin of 2 to 1.

"Even though the plaintiffs alleged a well-founded fear that their communications were subject to illegal surveillance, the court dismissed the case because plaintiffs could not state with certainty that they had been wiretapped by the National Security Agency," the ACLU said in a statement Friday following the decision.

ACLU Legal Director Steven R. Shapiro commented on the court's verdict: "We are deeply disappointed by today's decision that insulates the Bush administration's warrantless surveillance activities from judicial review and deprives Americans of any ability to challenge the illegal surveillance of their telephone calls and e-mails. As a result of today's decision, the Bush administration has been left free to violate the Foreign Intelligence Surveillance Act, which Congress adopted almost 30 years ago to prevent the executive branch from engaging in precisely this kind of unchecked surveillance.

"It is important to emphasize that the court today did not uphold the legality of the government's warrantless surveillance activity," Shapiro said. "Indeed, the only judge to discuss the merits clearly and unequivocally declared that the warrantless surveillance was unlawful."

Shapiro said the ACLU was "currently reviewing all of our legal options, including taking this challenge to the U.S. Supreme Court."

Opposition to the NSA program continues to mount from within the Democratic-controlled 110th Congress.

On June 27 Sen. Patrick Leahy, D-Vt., the chairman of the Senate Judiciary Committee, subpoenaed the White House, Vice President Dick Cheney and the Justice Department for documents on the program.