With yesterday's near-sweep of Super Tuesday primaries, Sen. John Kerry has consolidated his earlier winning streak and become the party's clear choice for the Democratic presidential nomination.

Later today Sen. John Edwards will bow out of the race, after a campaign that defied expectations nearly as much as Kerry's, fueled by an upbeat message and an array of new policy ideas. His challenge to Kerry over the last few weeks has managed to strengthen, not weaken, the nominee's position, as witnessed by the high and rising approval ratings for both candidates among primary voters, and the growing strength of the party as a whole among the entire electorate.

Kerry has ended the nominating process much as he entered it toward the end of 2002: a deeply experienced and knowledgeable leader determined to offer Americans a clear alternative to George W. Bush, and capable of putting together a broad coalition of Democrats, independents and disappointed former Bush supporters. By surviving months on the political intensive care list before reviving his campaign with a victory in Iowa, he demonstrated a toughness and self-discipline that will serve Democrats well in a long general election campaign, and will serve his country well if he is elected.

But general elections are different from nominating contests, and involve a conversation with the whole country, including many millions of swing voters who know relatively little about the challenger, and who have mixed opinions about the incumbent. The Democratic candidate cannot simply "Kerry on" with his primary-season campaign; he must quickly define himself positively to a new audience before the opposition defines him negatively.

As Kerry acknowledged last night, the White House and the Republican Party will immediately unleash the dogs of political war, and in the absence of a presidential record they can defend, will attempt to turn back the rising tide of Democratic prospects with a savagely negative campaign financed with big sacks of special interest cash. Their lines of attack will be highly reminiscent of those they unsuccessfully pursued against Bill Clinton in 1992 and 1996, simultaneously calling Kerry a devoted old-fashioned liberal and an unprincipled "waffler."

Like Clinton, Kerry should be able to forcefully rebut this contradictory assault. Yes, he has long represented a Massachusetts constituency that's liberal by national standards. And yes, like any thoughtful leader, his views do not conform to simple-minded ideological litmus tests that rule out nuanced positions, efforts to build political coalitions, or modern policy ideas to reflect changing times. Like many who have watched him over the years, we think his record and his agenda for the country show a thoughtful, imaginative, reform-minded leader with clear principles and an understanding that complex challenges often require real new ideas, not partisan orthodoxy.

As a charter member of the Senate New Democrat Coalition, Kerry has often rejected the stale left-right options that disguise the real choices facing the country -- choices that are rarely reflected in mechanical interest-group Congressional vote ratings, but that are in line with the real sentiments of the American people.

As a Blair Democrat and a proponent of a tough-minded progressive internationalism, Kerry understands that America's security and our influence in a dangerous world depend on both a willingness to use America's military might and a willingness to advance our values in concert with countries that share them.

As a long-time deficit hawk and supporter of key reforms in welfare and education, Kerry believes that traditional progressive goals must be pursued through modern means and a determination to bend the creaky machinery of government to the popular will.

And as a true war hero and a powerful advocate of national service, Kerry will not tolerate attempts by the GOP to hijack mainstream American values and deploy them in a divisive and distracting battle of cultural stereotypes.

We suspect the more voters learn about John Kerry's actual views, the more they will be inclined to say: "If this is a waffle, bring on the syrup."

If his candidacy becomes, to quote the title of his campaign manifesto, "A Call to Service," and his message and agenda offer the kind of politics of higher purpose he has so often embraced, then we suspect the GOP attack machine will quickly run out of gas. Then this presidential election can be a true referendum not only on George W. Bush's broken promises and dubious record, but also on the real choices facing the American people at home and abroad.