June 28 (Bloomberg) -- The Bush administration asserted executive privilege and rejected subpoenas from two congressional committees probing last year's firings of eight U.S. attorneys.

``The president has decided to assert executive privilege and therefore the White House will not be making any production in response to these subpoenas for documents,'' White House Counsel Fred Fielding wrote to Senator Pat Leahy of Vermont and Representative John Conyers of Michigan, chairmen of the Senate and House Judiciary Committees.

The White House resistance is likely to touch off a constitutional showdown over Congress's ability to investigate the prosecutor firings and the president's ability to obtain frank counsel from advisers.

Conyers, a Democrat, said the privilege claim won't end the fight for the documents.

``The president's response to our subpoena shows an appalling disregard for the right of the people to know what is going on in their government,'' Conyers said in a statement. ``The executive privilege assertion is unprecedented in its breadth and scope, and even includes documents that the administration previously offered to provide.''

New York Democrat Charles Schumer, who has been leading the Senate Judiciary Committee's probe of the prosecutor dismissals, said the White House is ``stonewalling'' Congress.

`Large' Questions

``The U.S. attorney scandal has put forward large, looming questions,'' Schumer said at a committee meeting today. ``The subpoenas were an attempt to get answers.''

He likened the White House's refusal to turn over the documents to the Watergate scandals during President Richard Nixon's administration.

``Not since the Nixon administration have we seen a stonewalling strategy like this,'' Schumer said. ``I have no doubt it will backfire and it will not stand.''

White House press secretary Tony Snow told reporters aboard Air Force One, as Bush was flying to Newport, Rhode Island, for a speech, that it was ``premature to talk about courts. It's really up to Congress now.''

The next likely step is for Congress to vote -- probably after its July 4 recess -- to hold White House officials in contempt of Congress, Carl Tobias, a law professor at the University of Richmond in Virginia, said in an interview.

``Then Congress will try to have it enforced in the courts,'' he said. ``There are good arguments on both sides but I believe Congress has the better of it,'' Tobias said, citing its constitution powers to investigate.

`Getting Along'

Pennsylvania Senator Arlen Specter, the top Republican on the Judiciary Committee, told reporters that lawmakers should accept Bush's offer to let White House aides answer questions behind closed doors without a transcript. A court battle over the executive privilege claim would take two years to resolve and by then the president's term will have ended, he said.

``I'd like for the committee to get along with the White House,'' Specter said. ``If we started getting along, we'd find out what the facts are.''

Specter said that as long as the investigation continues to lag, ``Attorney General Gonzales continues to serve'' and the Justice Department remains in ``total disarray.''

A senior administration official, on a conference call with reporters, said the White House is confident its assertion of executive privilege would withstand a court challenge.

`Utmost Importance'

Fielding, in his letter to lawmakers, said ``the principles at stake here are of the utmost importance.

``Presidents must be able to depend upon their advisers and other executive branch officials speaking candidly and without inhibition while deliberating and working to advise the president,'' he wrote.

The congressional committees sought documents that would shed light on the dismissal of the eight U.S. attorneys and whether they were fired for political purposes.

Harriet Miers, former White House counsel, and Sara M. Taylor, former White House director of political affairs, were among those subpoenaed. Bush has ordered Miers and Taylor ``not to produce any documents,'' Fielding said.

Bush has offered to let Congress question his aides privately without a transcript.

Fielding's letter reiterated the president's previous offer, saying, ``in the absence of any subpoenas he continues to be willing to provide you with information as previously offered.''

`Balanced Manner'

This approach, Fielding said, would allow the congressional inquiry to ``proceed in a balanced manner, respectful of important constitutional principles of both institutions, rather than through confrontation.''

Earlier documents released by the Justice Department show that Miers once discussed firing all 93 U.S. attorneys, a proposal resisted by the Justice Department. She consulted closely with Attorney General Alberto Gonzales's then-chief of staff, Kyle Sampson, about the plans to replace eight prosecutors.

Congressional investigators are trying to determine whether the prosecutors were fired for improper political motives such as to spur investigations of Democrats or squelch those of Republicans.

To contact the reporters on this story: Roger Runningen in Washington at rrunningen@bloomberg.net; Edwin Chen in Washington at echen32@bloomberg.net.

Last Updated: June 28, 2007 16:24 EDT