A spokeswoman for Mr. Cheney said his office would respond later, while a Justice Department spokesman said, “The department will continue to work closely with the Congress as they exercise their oversight functions, and we will review this matter in the spirit of that longstanding relationship.”

Under the domestic eavesdropping program, the N.S.A. did not obtain warrants before listening in on phone calls and reading e-mail messages to and from Americans and others in the United States who the agency believes may be linked to Al Qaeda. Only international communications — those into and out of the country — were monitored, according to administration officials.

The Senate panel’s action comes after dramatic testimony last month by James B. Comey, former deputy attorney general, who described a March 2004 confrontation at the hospital bedside of John Ashcroft, then attorney general, between Justice Department officials and White House aides over the legality of the wiretapping program.

Before Mr. Comey’s testimony, the White House had largely been able to fend off aggressive oversight of the N.S.A. wiretapping since it was first disclosed in December 2005. The Republican-controlled Congress held hearings last year, and even considered legislative proposals to curb the scope of the eavesdropping. But Mr. Cheney repeatedly pressured Republican Congressional leaders to pull back.

When the Democrats won the 2006 midterm elections, many observers predicted that the N.S.A. program — which a federal judge declared unconstitutional — would be one of the first Bush administration operations to undergo new scrutiny. But in January, the administration announced that it was placing the program under the legal framework of the Foreign Intelligence Surveillance Act, a move it had previously refused to consider.

The Democrats have largely focused on objections to the Iraq war in their first months in power, and have appeared reluctant to take aggressive steps to challenge policies on harsh interrogation practices, secret Central Intelligence Agency prisons and domestic wiretapping for fear of being labeled soft on terrorism.

For instance, at a confirmation hearing on June 19 for John A. Rizzo as general counsel of the C.I.A., no member of the Senate Intelligence Committee directly challenged the agency’s secret detention or harsh interrogation practices.