WASHINGTON — CIA director R. James Woolsey, under fire for months for his handling of the Aldrich H. Ames spy case and lacking strong support in the White House and Congress, resigned abruptly on Wednesday.

The nation's first post-Cold War spy chief never forcefully seized control of a sprawling, $30-billion-a-year intelligence bureaucracy and was not seen by his own employees or by his overseers on Capitol Hill as a strong advocate of intelligence programs.

White House officials said Woolsey's resignation, communicated to President Clinton in a letter dated Monday, came without warning and was not requested by the President.

Clinton said he accepted Woolsey's resignation "with regret," but aides indicated he did not try to talk Woolsey out of leaving when the two men spoke by telephone on Monday.

"Jim Woolsey has been a staunch advocate of maintaining an intelligence capability that is second to none," Clinton said in a written statement that was notable for its mild praise and impersonal language. "Jim Woolsey deserves the gratitude of all Americans for his service to our country. He has my deep appreciation."

Woolsey, 53, cited a desire to spend more time with his family as chief among his reasons for his resignation, effective at the end of January.

"In making the decision to return to the private sector . . . my family figures prominently," Woolsey said in a statement. "For their patience and understanding in the face of lost evenings, weekends and holidays, it is time for recompense."

A White House official said a successor has not yet been chosen. Among those whose names surfaced as rumors of Woolsey's imminent departure spread is Deputy Defense Secretary John M. Deutch, the second-ranking official at the Pentagon.

Another potential successor, defeated Democratic Rep. Dan Glickman of Kansas, the outgoing chairman of the House Intelligence Committee, was named agriculture secretary on Wednesday.

Glickman is known to have told Clinton that the President should get more personally involved in intelligence issues, and he has also criticized Woolsey publicly and privately for his response to the Ames case and other internal agency problems.

Insiders say morale at the Central Intelligence Agency is at its lowest point in nearly 20 years, following the collapse of its main surveillance target--the Soviet Union--a succession of scandals, budget cuts and questions about its very reason for existence.