President Clinton has struck an extraordinary bargain, agreeing to nominate a prominent conservative selected by a Republican senator to an important appeals court post, in exchange for the confirmation of one of his nominees to the same court, Senate and administration officials said on Monday.

In exchange for nominating the Republican choice, Judge Barbara Durham, the chief justice of the Washington state Supreme Court, to the 9th U.S. Circuit Court of Appeals in San Francisco, the Republicans agreed to stop blocking the nominations of several Clinton nominees, including that of Professor William Fletcher.For more than three years, Senate Republicans have steadfastly refused to act on the nomination of Fletcher, 52, a longtime Clinton friend who teaches law at the University of California at Berkeley.

But Fletcher now appears head-ed for confirmation as a result of Clinton's private agreement to nominate Durham, 55. The officials said that Clinton had made the deal largely with Sen. Slade Gorton, R-Wash.

Durham has been called the most conservative state Supreme Court judge in Washington.

Republicans, who control the Senate calendar, have told the White House that they would allow a vote on Fletcher's nomination only after Clinton nominates Durham. The White House has begun preparing for her formal nomination, asking the FBI to complete a background check.

Though the process of nominating and confirming judges is rife with politics and trade-offs, the Clinton-Gorton arrangement is highly unusual. A senior administration official acknowledged that Durham would never have been considered as a suitable nominee if not for the eagerness to have Fletcher confirmed.