"The irony to me is he was so inspiring and so well informed on so many issues, yet his candidacy will only serve to support the election of those most hostile to his issues," Pearce said. "I ironically continue to be inspired by Nader and very disappointed in his decision."
Nader and the Green Party, on whose ticket he ran in 2000, have steadfastly refused to take responsibility for Gore's defeat. They blame the Democrat's campaign, shenanigans in the Florida election and the intervention of a conservative Supreme Court for the defeat.
Nader dismissed the criticism of his candidacy as coming from "the liberal intelligentsia" -- people concerned about the same issues, but willing to settle for "the least worst option." He described himself as a lifelong progressive, part of a group that was "tougher in their struggle for justice."
Other self-described progressives disagreed. Rep. Bernard Sanders (I-Vt.) said in a statement that Nader could end up "splitting the vote with the candidate. Middle-income and working families just cannot afford four more years of Bush."
Dante Scala, a research fellow at the New Hampshire Institute of Politics at St. Anselm College in Manchester, said Nader is unlikely to do as well as he did in 2000 because Democrats are much more united in 2004. But if the election were close, Nader's presence could tip a state or two, Scala said, including states that Gore carried in 2000.
Tony Quinn, a former Republican consultant in Sacramento who is involved in nonpartisan political analysis, said third-party candidates always do the most damage to candidates who are ideologically similar.
To avoid this, Nader supporters, many chastened by the 2000 election, have tried to mount vote-swapping arrangements. They would allow those who live in swing states to vote for the Democrats, while Democrats who live in solidly Republican or Democratic states would vote for Nader.
The deeply divided Green Party will decide at its Milwaukee convention in June whether to nominate another candidate, try to redraft Nader, not run a candidate at all, or run hard only in non-swing states, spokesman Scott McLarty said.
"People who voted for him the last time recognize they made a mistake, and they won't do it again," predicted Iowa Gov. Tom Vilsack, who is chairman of the Democratic Governors' Association. "He won't have the resources to mount a major campaign, and people are focused on solutions, not symbols."
Nader has said that Americans should vote their conscience. Among his ideas are better public financing of elections, restrictions on corporate funding and a chance for voters to say they don't like any of the candidates and force a reelection.
These issues do not have anything to do with Nader's hopes of winning the presidency. Even as volunteers recruited through his Web site -- www.votenader.org -- try to get his name on the ballot, Nader acknowledged the election is only part of a broad scheme to involve people in political activism, and to draw attention to issues that the major parties would rather ignore.
If the Democrats paid real attention to the issue of corporate malfeasance, he would be delighted, Nader said. "It's up to them to grab away my votes and my issues," he said.
Staff writer David S. Broder contributed to this report.