Defiant on the day after, Green Party nominee Ralph Nader told a growing chorus of liberal critics yesterday that he bears no responsibility for the outcome of the presidential race in Florida, where Texas Gov. George W. Bush holds a slim lead over Vice President Gore in the state that will determine who captures the White House.

"I've always said that it was Al Gore's election to lose, that only Al Gore could beat Al Gore," Nader told reporters at a Washington news conference. "If Democrats are disappointed with the returns, they need to take a long, close look at their party and the empty campaign waged by Al Gore."

Gore is widely perceived to have run a tactically poor campaign, but if he loses, Nader will have played an unmistakable role. In Florida, the anti-establishment Nader attracted voters who otherwise would have chosen the Democratic nominee, exit polls show, collecting 96,900 votes in a state where Gore stands just 1,433 votes behind Bush.

Nader also altered Gore's campaign endgame by challenging for votes in states critical to the Democrat's hopes. Faced with a threat from the left, Gore was forced to spend unexpected energy and shift his strategy to avoid losing Oregon, Washington and several other key states where Nader polled strongly.

At a news conference yesterday, Nader called charges that he took votes from Gore "the most impudent assertion" of the campaign. He said the Green Party rightfully fought hard, earned 2.6 million votes and emerged as a "a viable political force" that will only grow stronger.

"By the way," Nader joked, "I do think that Al Gore cost me the election, especially in Florida."

But liberal opponents of Nader's candidacy were livid nonetheless. His critics believe the White House would be safely in Democratic hands, to the benefit of more progressive causes, if only Nader had relinquished his Green Party quest in favor of pragmatism.

AFL-CIO President John Sweeney called the Nader campaign "reprehensible." Environmental Working Group President Ken Cook said that if Bush wins, Nader will have delivered a "true nightmare to the progressive community."

"The public interest community is going to spend tens of millions of dollars a year for the next four years playing defense," said Cook, who scoffed at Nader's claims of Green Party viability.

"I don't think he's going to build a Green Party any more than O.J.'s out there looking for the murderer," he said.

The leader of the National Abortion and Reproductive Rights Action League said Nader will be responsible for setbacks to women's causes if Gore is defeated. The group ran ads in seven states before the election warning that a vote for Nader would be equivalent to a vote for Bush.

"He cost Al Gore the race. Not only by what happened in Florida, but by making these other states a threat to Al Gore," said Kate Michelman, NARAL's president. "Not to recognize what was at stake--or to dismiss it if he did--was dangerous and represented a type of arrogance. As a result, he has lost a lot of credibility."

The Green Party won 3 percent of the national vote, short of the 5 percent needed to earn public funds in the 2004 campaign. Nader said yesterday that the money was "more of a convenience than a necessity." He noted that the party collected at least 5 percent in 11 states, including 10 percent in Alaska.

Although Nader, 66, said there are too many variables to determine whether his departure from the race might have assured a Gore victory, Nader voters suggested in national exit polls that they would have chosen Gore over Bush by 47 percent to 21 percent in a two-person race.

Nader himself was unapologetic.

"Democrats must now either find their progressive roots or watch the party gradually wither away, or basically become a crypto-Republican Party, bidding for the same money and, increasingly, for the same voters," Nader said. "America can do better, much better."

Looking ahead, Nader said the Green Party intends to strengthen its grass-roots organization, win local offices and pressure what he calls the "two-party duopoly." Asked what his role would be in a party he never joined, he said, "I'm going to certainly help."

The party's ability to become the force foreseen by Nader is in some doubt, according to several analysts. The Greens themselves are divided, as are potential allies who supported the party Tuesday.

"It's not really a political party. It's somewhere between an experiment and a movement. It's not well-organized. His constituency is a bit unclear," said Georgetown University professor Michael Kazin, author of "The Populist Persuasion."

"The bottom line," Kazin continued, "is to have a third party with any durability, you have to have some constituency that really is loyal to your party, who really thinks the two parties are not addressing their needs."

Princeton University politics professor Larry Bartels is another skeptic.

"Look at the history of the parties who have gotten 5 percent," Bartels said. "They tend almost always to fade away. I think the Greens are very unlikely to be a major force."

Nader contended in campaign appearances that a Bush presidency could energize progressives. Washington writer John Judis, who opposed the Nader candidacy, predicted that much of that energy could be directed at Nader himself.

"I suspect a lot of the people who voted for Nader this time are going to learn their lesson," Judis said. "I think they thought seriously that voting was a matter of conscience, like something you do in a confessional or a church. But politics is a process of compromise, bringing diverse groups together in order to build a major force.

"That's exactly what Nader and the Green Party didn't understand."