Thirty-five years ago, William F. Buckley Jr. founded National Review, a conservative magazine that set itself a preposterously ambitious goal. "It stands athwart history yelling Stop," the magazine said of itself in its first editorial.

Yesterday, 2,750 issues later, Buckley quietly said Stop himself and announced that he was stepping down as National Review's editor in chief.

In financial terms, the announcement was without significance. Buckley will continue to hold all of the National Review stock, which, he noted, "commercially is about as valuable as Confederate bonds." And he pledged to look over the shoulders of his editors to keep the magazine on track, lest he risk "being designated at some point in the future as another King Lear."

In the world of magazine publishing, the announcement was somewhat more significant: Since William Shawn's retirement as editor of the New Yorker, Buckley noted, he has been the nation's most senior magazine editor.

But it is in political and intellectual terms that the announcement must be judged, and seen that way the event is, as Buckley might put it, of hippopotamic proportions. The retirement of the editor who gave us the phrase, "Don't imminentize the eschaton" -- and the politics and theology behind it -- is a phenomenon of consequentiality.

Buckley, who will retire the title editor in chief, leaves the magazine at a point when history finally seems to be heeding National Review's original admonition.

Buckley is quite content, thank you, with communism's collapse. But the 64-year-old controversialist and writer of anti-communist thrillers admits that the world will not be the same without communism to kick around.

"Taking the Cold War away from me," he said in an interview, "is like taking horses away from Dick Francis."

Still, liberalism will keep him busy. "I think of liberalism," he said, "as a kind of virus, against which there is not a dispositive remedy." Speaking as an exorcist would of Satan himself, Buckley pledged to continue the struggle against "our enemy, wherever our enemy appears, in whatever form he appears."

It is, quite simply, impossible to overestimate the importance of Buckley's magazine in the history of postwar American politics. John Judis, Buckley's biographer and a liberal who cannot be accused of sympathy for National Review's cause, put matters definitively.

"The role of National Review was to create, almost out of nothing, the conservative movement," Judis said. "Before National Review, there were conservatives, but there was not a body of ideas that created the basis for the conservative movement."

Indeed, 1955, the first year of National Review's life, was a bad time for conservatives of Buckley's bent. Joe McCarthy had just been brought down and Dwight Eisenhower stood astride the Republican Party pledged, as Buckley once put it, to "govern in such a fashion as to more or less please more or less everybody."

Buckley and his magazine pledged to fight this sort of blandness. In their opposition to "the liberal establishment," the Buckleyites curiously prefigured the New Left, which later waged war against "establishment liberalism."

"Middle-of-the-road qua middle of the road is politically, intellectually and morally repugnant," Buckley said at the time.

"I want some positively unsettling vigor," he said, "a sense of abandon, and joy and cocksureness that may, indeed, be interpreted by some as indiscretion."

Although we think of conservatism now as a reasonably coherent creed, it was National Review that did the philosophical footwork to make it so.

National Review combined, in varying doses, free market economics, traditionalist philosophy (with a heavy Roman Catholic lilt) and an anti-communist foreign policy.

This was quite new, since many of the free marketeers had little patience with traditionalism. Traditionalists often had little use for capitalism. And until the 1950s, conservatives were isolationists who had little use for the global war against communism that National Review preached.

This new philosophical brew was dubbed "fusionism" by Frank Meyer, one of Buckley's associate editors whose appropriately titled column, "Principles and Heresies," captured National Review's sense of itself as the arbiter of conservative orthodoxy.

The rest, as they say, is history, history that culminated with the election of National Review's great friend Ronald Reagan in 1980.

In looking back, Buckley believes that the magazine's most important accomplishment was "the absolute exclusion of anything antisemitic or kooky" from the conservative movement. One of National Review's most notable battles was waged against the John Birch Society.

In his interview this week, Buckley also said he was proud of his magazine's "near-absolute respect for the cultural aspects of conservatism.

"The idea that conservatives should just be interested in the profit motive," Buckley said, "I just find humiliating."

Under the new configuration of power at National Review, Buckley will carry the thoroughly appropriate title of "Editor-at-large." John O'Sullivan, a former reporter for the London Daily Telegraph who has carried the title of editor at National Review for two years, will now be the editor in complete fact. Wick Allison will continue as publisher.

"It is inconceivable to me, having watched them in operation for over a year, that I have made a mistake," Buckley said, adding that he hopes to decide someday to whom he will turn over full ownership of the magazine.

In the text of a speech he planned to deliver last night at a valedictory dinner at the Waldorf-Astoria in New York, Buckley recalled that one of his favorite tasks as editor was to pick a paragraph to lead the magazine's editorial section. He remembered two with special fondness.

One of them went: "The attempted assassination of Sukarno last week had all the earmarks of a CIA operation. Everyone in the room was killed except Sukarno."

His other favorite was about a magazine with which National Review has developed more ideological and personal empathy in recent years. The line went: "Gerald Johnson of the New Republic wonders what a football would think about football if a football could think. Very interesting, but not as interesting as, What would a New Republic reader think of the New Republic if a New Republic reader could think?"

"I have not scheduled the discontinuation of my column, or of 'Firing Line,' or of public speaking, or of book writing," Buckley said. "But these activities, by their nature, terminate whenever the Reaper moves his supernatural, or for that matter, democratic hand, whereas National Review, I like to think, will be here, enlivening right reason, for as long as there is anything left in America to celebrate."