For months, Democrats, longtime friends and former supporters of Ralph Nader (search) have urged him not to make another run for president.

Now that the consumer advocate has formally declared his candidacy as an independent, many Democrats fear a repeat of the 2000 race, when Nader was blamed by some for taking just enough votes away from Al Gore (search) to secure a razor-thin victory for George W. Bush.

Nader rejects the spoiler label as a "contemptuous" term used by those who want to deny voters a choice. Declaring Washington a "corporate-occupied territory," he has accused both Democrats and Republicans of being dominated by corporate lobbyists who care little about the needs of ordinary Americans.

Nader, who turns 70 this week, was to lay out his campaign themes — including universal health care, campaign finance reform, fighting poverty and addressing environmental concerns — at a press conference Monday in Washington before campaigning in Texas later this week.

"It's a question between both parties flunking. One with a D-, the Republicans, one with a D+, the Democrats, and it's time to change the equation and bring millions of American people into the political arena," Nader said on NBC's "Meet the Press," where he made his announcement Sunday.

But even old friends like liberal Vermont Rep. Bernie Sanders, the only independent in the House, called Nader's decision "counterproductive," predicting "virtually the entire progressive movement is not going to be supportive of Nader."

Democratic National Committee chairman Terry McAuliffe, who personally urged Nader not to run, called the decision "unfortunate."

"You know, he's had a whole distinguished career, fighting for working families, and I would hate to see part of his legacy being that he got us eight years of George Bush," McAuliffe said Sunday on CBS' "Face the Nation."

Sanders and others also suggest that Nader will not pull close to the 2.7 percent of the vote he won in 2000 — when he ran on the Green Party ticket — because he will have a difficult time getting on many state ballots without the backing of an established party or major financial resources.

Ballot access experts say an independent needs a total of about 700,000 signatures to get on the ballot in all 50 states, a prospect Nader likened to "climbing a cliff with a slippery rope."

But he is undaunted, saying he is confident he can collect more than the $8 million he raised in 2000 using the same Internet fund-raising strategies that former Vermont Gov. Howard Dean employed before dropping out of the race. As always, he will rely on small contributions and refuse money from corporations and political action committees.

Democratic officials issued a statement Sunday saying Nader has promised McAuliffe he will not criticize the Democratic nominee, but rather focus candidacy against the Bush administration.

Nader acknowledged the pledge but said it does not mean he will refrain from criticizing Democrats if they attack him. "I'm not going to avoid responding," he said.