The Senate Judiciary Committee has authorized subpoenas for documents describing the legal rationale behind the president's domestic wiretapping program.
The spying program has come under new scrutiny since a former Justice official described White House efforts to override the Justice Department's assessment that the program was illegal.
For more than a year, the Senate Judiciary Committee has been trying to get copies of the legal justification for the president's domestic spying program. The White House and Justice Department have refused to hand them over.
Now the White House wants Congress to amend the Foreign Intelligence Surveillance Act — the law that governs domestic spying. Sen. Russ Feingold, a Democrat from Wisconsin, said Congress can't act until it knows more.
"How can this committee even consider legislation amending a law when most of us on this committee don't even know how the executive branch or the judicial branch interprets that law?" asked Feingold.
Sen. Patrick Leahy, the Vermont Democrat who chairs the Judiciary Committee, said he is only pursuing subpoenas because the administration has been unwilling to cooperate.