Ralph Nader announced Monday that he will run for the Green Party presidential nomination. (AP Photo)

He said he hopes to get on the ballots in as many as 45 states and win as much as 5 percent of the vote, diluting the support of both the Republicans and Democrats. "Politicians of these two parties only look back when you take away their vote," he said at a news conference.

Nader, the consumer advocate lawyer who first gained prominence taking on the auto industry in the 1960s, received less than 1 percent of the vote when he ran in 1996. He spent less than $5,000, taking no contributions and personally financing his campaign.

In 1992, Nader collected about 6,300 write-in votes in the New Hampshire primary, sometimes drawing crowds that rivaled those of major-party candidates.

Nader, who turns 66 this month, has pressed for campaign finance overhaul, environmental protection, workers' rights and trade-law changes, employing a network of nonprofit organizations.

He faces competition for the Green Party nomination from at least three other candidates, including Jello Biafra, lead singer for The Dead Kennedys.

Nader often shows disdain for the political process and has suggested that the Republicans and Democrats leave voters with a choice between "Tweedle-Dum and Tweedle-Dee." He thinks third parties offer voters an alternative.

He spoke today of a "widening democracy gap" created by control of the political government by "the corporate government."

"Active citizens are left shouting their concern over a deep chasm between them and their government," he said.

He said he will raise money this time but "not for political consulting firms or expensive 30-second ads. We will raise money for full-time staff to support the wide-ranging efforts of volunteers."