John Kerry's acceptance speech Thursday night, the climactic and only consequential moment of the Democratic National Convention, will probably give him a bounce in the polls. Such speeches usually do: Since 1976, Democratic nominees have gotten bigger convention boosts than Republicans, sometimes large, sometimes temporary. But more important is what the speech and its reception tells us about the party and its nominee.

 When I started attending Democratic conventions in 1968, the question was whether the love the winning nominee had earned from his supporters would transfer to those who had backed another horse. Would Jesse Jackson delegates bond with Michael Dukakis?

 This year the question was different. The Democratic delegates, almost all selected by the Kerry campaign, came to Boston joined not by love of John Kerry but by hate for George W. Bush -- and all they believe he stands for. They saw in Kerry, the decorated Vietnam veteran, the best tool to beat Bush. The assumption by Kerry strategists was that a majority of the country's voters have already rejected Bush. (James Carville, on the afternoon of Kerry's speech, qualified this some by saying that a majority was as close to rejection as you can get.) The task then was to establish Kerry as an acceptable alternative, and in particular as a commander in chief who would defend America against attack.

 Kerry, like John Edwards the night before, mouthed those words with some vigor. But more than Edwards, he struck an equivocal, nuanced note. He went on at much greater length about the need for, in the convention slogan, ?respect in the world." He talked about responding to an attack rather than, as George W. Bush does, of taking the fight to the enemy.

 When he pledged to ?build a stronger American military" -- a pledge that would have brought a roar of approval at a Republican convention -- he was met with silence. When he threw zingers at George W. Bush, which he did frequently despite his calls for bipartisanship, he was met with prolonged cheers. To get the ringing reception he needed in the hall, he indulged in the Bush-bashing that his strategists have been saying turns mid-electorate voters off.

 As in the primaries, the most effective campaigning for Kerry came not in his own speeches, but in the testimony of others -- his daughters, the film footage he had made of his service in Vietnam, his ?band of brothers," former Sen. Max Cleland. His treatment of domestic issues was a hurried reading of the laundry list of Democratic proposals, so long as to leave any particular plank forgotten, in contrast to the disciplined concentration on a few points of George W. Bush in 2000 or Bill Clinton in 1992. If you talk about everything, it sounds like you are talking about nothing.

 But are Kerry's strategists right when they say that the majority of voters have conclusively rejected George W. Bush? I made the same assumption about Bill Clinton in 1995-96, and I was wrong. The voters, or the increasingly small percentage of persuadable ones, were listening to their president -- as they may be now. This campaign moment won't stay frozen in time. The Bush strategists proclaim that even before their convention at the end of August, they'll make the case that Kerry's resolute words about defending America are undercut by the resolute statements he's made on all sides of the Iraq issue in the past, compiled by the Republicans in a devastating 11-minute video.

 They also say their candidate will be addressing the voters' perfectly reasonable question: What will you do in a second term? John Kerry and John Edwards have told us some, but not much of what they'd do; Bush has said (unwisely, in my view) even less. Social Security and Medicare face financial crises; the Alternative Minimum Tax needs to be changed, or it will start hitting millions of taxpayers; the mullahs' Iran will probably get nuclear weapons between now and 2008. Kerry flicked past the first two of these problems and suggested that he will not do anything about the third without evidence strong enough to stand up in court.

 Kerry's speech and convention may have given him a bounce. But it's not likely to be the last bounce in this excruciatingly close and consequential election.