Is Kosovo the defining moment of a presidency?

On April 22, President Clinton said the murky proposal that Russian ex-Premier Viktor Chernomyrdin had brought from Belgrade "represents, I suppose, a step forward."

Within hours, British Prime Minister Tony Blair had shot it out of the water and, next morning, the two leaders said jointly that the proposal fell "well short" of NATO requirements.

All through the summit, Mr. Blair sounded tougher than Mr. Clinton, more willing to use ground forces, more ready to fight as long as it takes.

In the end, the president had to plead with him to leave the subject of ground forces out of the final communiqu.

In the years of this historic transatlantic special relationship, it was not the first time that little Britain, with far fewer resources and far smaller margin for error, showed willingness to take greater risks.

In August 1990, President Bush was not immediately inclined to go to war with Iraq over the invasion of Kuwait. But he met with Prime Minister Margaret Thatcher, both happening to be in Aspen, Colo., and she was reliably reported to have told him, "Mr. President, this is no time to go wobbly on us."

Winston Churchill, of course, was the legendary hawk, pressing Franklin Roosevelt to open a second front against Hitler - that is, to invade Europe.

It seems fitting that Winston Churchill III now, recalling in The Wall Street Journal his grandfather's famous "Victory at all costs" speech, should warn that if bombing Yugoslavia fails, then Clinton will be remembered as "the architect of the downfall of the world's most successful alliance."

Prime Minister Blair, returning to London, immediately went before Parliament to state that "we do not rule out any options," and the danger of a land invasion against "undegraded" Serb forces remains.

He said that NATO planners would update plans to cover all contingencies, and "meanwhile, the buildup of forces in the region continues."

More in tone than substance, Blair was presenting deliberately ambiguous summit agreements in their most belligerent terms. As with prime ministers and presidents past, he and Clinton speak the same language, but with markedly different accents.

Kosovo was probably the furthest thing from Clinton's mind on January 19 as his lawyers fought on the Senate floor to save his presidency and he prepared to deliver his State of the Union address to an uncertain reception.

On that Tuesday began the course of events that put NATO on the road to war with Yugoslavia.

In Belgrade, NATO generals were showing President Slobodan Milosevic photos of a Serbian massacre in the town of Recak.

Mr. Milosevic claimed the photos were staged.

In the Executive Office Building in Washington, the group of national security aides called "the principals' committee" met without the president, working on a new plan to threaten Milosevic with air strikes unless he accepted a peace agreement, took his troops out of Kosovo, and then let NATO troops in.

Until that time, Clinton tended to define his legacy in terms of domestic accomplishments. But history has a way of writing its own legacies.

Little did Harry Truman dream that, having risen to the task of completing Roosevelt's war, he would find his legacy amended to make room for the Korean War, the Marshall Plan, the Berlin airlift.

Little did President Carter imagine that his page in history would be blotted by the seizure of the American Embassy in Teheran.

Little did Richard Nixon think that his chapter in history would be dominated not by the breakthrough to China, but by the break-in at Watergate.

So now Clinton finds that Kosovo, which he originally considered to be a minor nuisance, like Bosnia, to be settled by threats and diplomacy, could come to consume his remaining time in office.

His domestic agenda - education, patients' bill of rights, Social Security - must share attention with the Balkans as Clinton pores over war plans and travels the country, drumming up public support.

He has come to see that this war could consume his domestic legacy as the Vietnam War came to consume Lyndon Johnson's Great Society.

The president now sees in Kosovo a clash of values, a clash of civilizations.

Who would have guessed that the ordeal of a couple of million ethnic Albanians would come to be the defining moment of his presidency?

Daniel Schorr is senior news analyst for National Public Radio.