It was, veterans of Bill Bradley's campaign agreed, an uncharacteristic but effective moment. At a Saturday morning rally at the Lions hall here, the normally cerebral presidential candidate who likes to challenge voters to live up to their better natures chose instead to challenge Al Gore's health plan by leading the crowd in an old-fashioned call-and-response chant. Hubert Humphrey would have been proud.

"Who's left out?" the crowd kept shouting gleefully, after a bit of coaching by Bradley. They were referring to the uninsured groups that Bradley's health plan would cover and Gore's wouldn't. "Al Gore won't tell you, so I will," Bradley would reply, listing yet another worthy constituency. Bradley clearly enjoyed his little venture into old-fashioned politicking.

If you like issues, you'll love the next six weeks of the Gore-Bradley struggle. This is a campaign fully engaged in arguments over health care, education and the reform of political money--and it's moving toward engagement on foreign policy as well. Yes, character will be important. But Bradley and Gore will use issues to hone their character points, as they did in their acerbic debate Sunday on "Meet the Press."

Bradley's willingness to engage Gore is a tribute to the campaign the vice president has run for the past 50 days. For most of 1999, Bradley rode above old political rules by offering inspiration. He struck a chord with liberal Democrats who share Bradley's desire to "dream again" and appreciate his big proposals. His disquisitions on integrity also played with moderate Democrats disgusted by President Clinton's troubles.

Bradley's gambit worked so well that Gore was forced to shake up his campaign and play the attacking underdog. Gore targeted Bradley's biggest idea, the health plan. It was too expensive, Gore said, would threaten the budget surplus and would leave no room for other initiatives. It was wrong to propose repealing Medicaid, the health program for the poor, and didn't leave enough money to shore up Medicare, the government's popular health program for the elderly.

Even some Bradley sympathizers concede that Gore asked legitimate questions. Many who respect Bradley's reach for universal coverage worry that his repeal of Medicaid could leave some among the poor worse off. And Bradley's claim in Friday's debate that little need be done about Medicare's finances in the short term will give Gore a new opening.

Worse for Bradley, his initially tepid reply to Gore's challenge played into doubts among potential supporters about whether Bradley was too sanctimonious to defend himself. "Voters like a candidate who stands up for principles and says what he believes is right," said a neutral Democratic pollster. "They don't like a candidate who says that these principles must be right because I'm the one who believes them." The danger for Bradley is that a righteousness voters admire can shade into a self-righteousness they mistrust. Bradley's joining the fray reduces the chances of that.

But Gore has now put new issues on the table. Gore's education plan lets him say that he, too, can think big and would do more than Bradley to push school reform. And Gore took some of the edge off Bradley's leading role in the battle for campaign finance reform by proposing on "Meet the Press" that both candidates simply stop running television and radio commercials. It was a naked but clever gimmick that grabbed headlines.

Gore's danger is the reverse of Bradley's: a seeming inability to do anything but attack. At two moments in Sunday's debate, Gore threw away chances to be gracious that would have done him no harm.

Bradley quietly let Gore off the hook for the 1996 campaign finance fiasco, noting the attorney general's investigation had in effect cleared Gore. Even so, Gore couldn't resist citing a newspaper editorial that spoke of "nauseating excesses" in some of Bradley's fund-raising. At that point, it was a jarring and unnecessary jab. And Gore couldn't let moderator Tim Russert's implicit critique of Bradley's vote against the Gulf War stand. Gore had to add that if Bradley's vote had prevailed, Saddam Hussein "would still be in Kuwait." It's a fair issue, but Gore lacked the self-discipline to let voters draw their own conclusions.

The most striking aspect of the Gore-Bradley confrontation, though, is how different it is from so many Democratic battles since 1968. There are no big gaps between Bradley and Gore on racial issues. Nor are they divided on cultural issues such as media and Internet violence, gay rights or the importance of the family. That Bradley and Gore agree on what problems will define the election--health care, education, campaign reform, the economy--may prove more important than all their squabbling between now and the day one of them emerges as a scarred but tested nominee.