HOWARD DEAN SOUNDED WORRIED. Last Wednesday in Burlington, Vermont, toward the end of his announcement that his presidential candidacy was over, Dean paused and looked directly at his audience of supporters. "Let me be clear," Dean said. "I will not run as an independent or third party candidate." Then Dean paused again. "And I urge my supporters not to be tempted to support any effort by another candidate." The governor's voice began to rise: "The bottom line is that we must beat George W. Bush in November--whatever it takes."

Why would Dean be worried? Two words: Ralph Nader. Democrats are concerned that if Nader runs for president in 2004, he will play the spoiler in the race, much as he did in 2000. Four years ago, the rap against Nader was that he siphoned off progressive voters from Al Gore and helped George W. Bush win the presidency. When you talk to Democratic strategists nowadays, they tell you that the party can't risk something like that happening again.

On Friday, Nader said he'll announce whether he's a presidential candidate on Sunday's "Meet the Press." But whatever Nader announces on Sunday, he certainly has been acting like a presidential candidate lately. Over the last five months, the consumer activist and former Green party presidential candidate has moved steadily toward another run. Last October, he set up a presidential exploratory committee. Beginning in January, he discussed his plans on a variety of television and radio talk shows. And in early February, he told Miles Benson,

When you listen to Nader talk about a possible candidacy, you are struck by how much he sounds like a man who has already made up his mind. For example, earlier this month on NPR, Nader discussed the three things he would need before running for president: a rationale, volunteers, and money. The rationale for his campaign would be (take a deep breath): "heralding the agenda of many subject matters and necessities of the American people that are not adequately emphasized or even discussed by the two parties." It's a "quite compelling" reason to run, he said. And Nader is "satisfied" with the number of volunteers that have pledged their support. That's two out of three. The only thing missing is fundraising, which is "still under [a] testing-the-waters framework."

Nader refused many requests to be interviewed for this article. But there is probably a reason why he is still testing the waters: A presidential run this year wouldn't simply be a replay of his 2000 campaign. For one thing, Nader won't be running as the Green party's presidential candidate. He rejected the idea in December, when he called various Green party leaders and told them he wouldn't run for the party's nomination. Nader later said the decision was logistical: The Green party doesn't formally nominate its candidate for president until June. And June is "too late" a date to mount a serious campaign, Nader told CNN's Bob Novak.

Also, some Democrats are confident that Nader's support has diminished. In 2000, Nader drew huge crowds: A November 2000 rally at the MCI Center in Washington drew more than 10,000 people. Another at New York City's Madison Square Garden drew 15,000 people. The crowds came at a price. Nader won 2.7 percent of the national vote in 2000--not enough for the Green party to receive federal matching funds, but more than enough for Nader to earn infamy among Democrats. Why? Look at the electoral results in two key swing states. In New Hampshire, Gore lost by a margin of 7,211 votes. Nader received 22,198. And in Florida, a state Al Gore lost by 537 votes, 97,488 people voted for Nader. "Nader was clearly an element in the campaign that arguably cost Gore the election," says Thomas F. Schaller, a political scientist at the University of Maryland.