WASHINGTON — The Senate Judiciary Committee chairman said yesterday he was ready to go to court if the White House resisted congressional subpoenas for information on the firing of federal prosecutors.

“If they don’t cooperate, yes I’d go that far,” Senator Leahy, a Democrat of Vermont, said. He was asked in a broadcast interview whether he would seek a congressional vote on contempt citations if President Bush did not comply. That move would push the matter to court.

“They’ve chosen confrontation rather than compromise or cooperation,” Mr. Leahy said. “The bottom line on this U.S. attorneys’ investigation is that we have people manipulating law enforcement. Law enforcement can’t be partisan.”

At issue is whether the White House exerted undue political influence in the Justice Department’s firing of prosecutors. Mr. Leahy’s hardening stance is pushing the Democratic-led investigation ever closer to a constitutional showdown over executive power and Congress’s right to oversight. The White House accused the committee of overreaching.

“After thousands of pages of documents, interviews and testimony by Justice Department officials, it’s clear that there’s simply no merit for this overreach,” presidential spokesman Tony Fratto said.

He said Mr. Leahy “is seeking access to candid and confidential deliberations from the president’s advisers — an intrusion he would never subject his own staff to. We have gone to great lengths to accommodate the committee in their oversight responsibilities.”

Separately, the Senate has subpoenaed the White House and Vice President Cheney’s office for documents related to the administration’s legal basis for conducting warrant-free eavesdropping on people in America. Mr. Leahy and Rep. John Conyers, a Democrat of Michigan, who heads the House Judiciary Committee, have demanded a White House explanation by July 9 as to its grounds for claiming executive privilege in refusing to turn over additional documents.

The two lawmakers say that regardless of whether the White House meets the deadline, they would begin acting to enforce the subpoenas as appropriate under the law.

Legal experts have been somewhat divided over the scope of a president’s power to shield information and ensure candid advice from top aides. The dispute, if it does head to court, could take months and ultimately outlast the remaining term of Mr. Bush’s presidency, which ends in January 2009.

Last week, White House counsel Fred Fielding said Mr. Bush was claiming executive privilege.

Mr. Leahy spoke on NBC’s “Meet the Press.”