WASHINGTON -- Consumer activist Ralph Nader launched an independent campaign for the White House yesterday, criticizing the Republican and Democratic candidates for not addressing issues "that are supported by a majority of the American people."

"You take that framework of people feeling locked out, shut out, marginalized, disrespected," he told NBC's Meet the Press. "You go from Iraq to Palestine/Israel, from Enron to Wall Street, from Katrina to the bungling of the Bush administration, to the complicity of the Democrats in not stopping him on the war, stopping him on the tax cuts, getting a decent energy bill through - and you have to ask yourself, as a citizen, should we elaborate the issues that the two [parties] are not talking about?"

This campaign is Nader's fifth try for the presidency. His greatest success came in 2000, again as the Green Party candidate, when he received more than 2.8 million votes.

Many Democrats blame Nader for George W. Bush's victory in 2000, arguing that Al Gore would have won Florida - and its 25 electoral votes - if Nader had not been in the race. Nader rejected that argument Sunday, saying Democrats were responsible for Gore's loss.

As for the current campaign, Nader was critical of the presumptive Republican nominee, John McCain, and Democrats Barack Obama and Hillary Clinton, saying they oppose full government-paid health insurance for all and failed to address what Nader described as "a bloated military budget."

Obama and Clinton dismissed the possibility that Nader's campaign would have a significant effect.

"His view is, unless it's Ralph Nader, that you're not tough enough on any of these issues," Obama said yesterday. "He thought that there was no difference between Al Gore and George Bush, and eight years later I think people realize that Ralph did not know what he was talking about."

On a flight yesterday to Providence, R.I., Clinton expressed disappointment in Nader's decision. "Obviously, it's not helpful to whomever our Democratic nominee is," the New York senator said. "But it's a free country."

But Nader's entry into the race was welcomed by Republican Mike Huckabee.

"I think it always would probably pull votes away from the Democrats, not the Republicans," the former Arkansas governor told CNN's Late Edition.

Leslie Hoffecker writes for the Los Angeles Times.