WASHINGTON (AP) -- A Supreme Court ruling striking down military commissions seriously weakens the foundation of the Bush administration's domestic surveillance program, critics said.

A congressional resolution President Bush relied on in creating commissions is a key rationale for the National Security Agency to listen in on phone calls without first obtaining a judge's permission.

The court reinforces our view that the NSA operation was unlawful, said George Washington University law professor Jonathan Turley. The Supreme Court cut away the administration's principal legal argument for the NSA operation.

Enacted a week after the Sept. 11 attacks, the congressional Authorization for Use of Military Force resolution cannot be seen as authorization for military commissions, the court ruled.

In January, the Justice Department invoked the resolution 92 times in a 42-page paper designed to quell the outcry that the White House had broken the law with its program of warrantless surveillance. A centerpiece in the administration's counter-attack against its critics, the DOJ entitled the white paper

Asked about the NSA program, a Justice Department official said after the ruling that I don't think the court had before it any other broader issues concerning the scope of the Authorization for Use of Military Force, except it clearly did recognize that it activated the president's war powers.

The official said the implications of the decision beyond military commissions is something that we are studying and will be studying. The official spoke on condition of anonymity because the matter is under review.

In the aftermath of the high court's ruling, lawyers for the Bush administration asked a federal appeals court in Washington to order more briefing on the decision's effect on civil lawsuits filed on behalf of hundreds of detainees held at the military prison at Guantanamo Bay, Cuba.

The NSA program faces a court challenge and the Supreme Court ruling gives new vigor to arguments that the administration does not have the power it says it has, said Anthony Romero, executive director of the American Civil Liberties Union.