Updated

Presidential hopeful John Kerry (search) accepted a challenge from John Edwards (search) Saturday and agreed to face off against the North Carolina senator in a debate.

The Democratic front-runner's campaign said the showdown will take place on Feb. 29.

The announcement follows Friday's news that consumer advocate Ralph Nader planned to announce his candidacy this weekend, according to his advisers.

Meanwhile, Edwards sought to make the case Saturday that his presidential campaign represents a fight for change that sets him apart from the Massachusetts senator and other Democrats.

"We can shine a bright light on what they're doing," said the first-term senator from North Carolina. Portraying himself as an outsider willing to buck entrenched interests, Edwards said he campaign was aimed at "pushing aside these lobbyists who stand between you and your democracy."

Edwards' campaigning Saturday was taking him from Hofstra University (search) on Long Island to Minnesota and Ohio. His populist pitch was focusing on toughening trade standards and offering aid for the middle class. Both, Edwards argued, are linked to established Washington powers that he opposes.

Edwards was trying to portray Kerry the establishment candidate who would do little in the way of change if he gets nominated.

"I've been in Washington long enough to see that power needs to change, see what the problems are," said Edwards. "I have seen this up close. They're drowning out your voice and the voices of most Americans."

Edwards surprised many with a strong second-place showing in last week's Wisconsin primary. In that state, he hammered trade deals, such as the North American Free Trade Agreement, which links the United States and Mexico and Canada, for allowing companies to ship thousands of jobs overseas and drive down wages in this country.

Edwards is sticking with that theme in many of the 10 states that are holding primaries on March 2, saying his message is resonating with voters.

He said his single term in the Senate has given him the insight he needs to understand what must change in Washington: lessen the influence of lobbyists.

On Saturday, he also took on companies that he said on making money from the U.S.-led war in Iraq.

"We've got to put a stop this war profiteering that's going on in Iraq," said Edwards. "If you were to put on a piece of paper a list of companies that have gotten contracts, then you put beside it a list of who they've made political contributions to, take a wild guess who that would be — George W. Bush."

Going into the pivotal March 2 contests, Edwards lacks Kerry's resources and is being more selective than the front-runner in where he campaigns and how he spends his money.

Edwards said he will begin television commercials in Ohio and Georgia but will spend less than what Kerry will purchase. Edwards said he has raised more than $4 million since his second-place showing in the Iowa caucuses and has the resources to push forward.

Return of Ralph Nader

Advisers to the 2000 Green Party candidate said Friday that he will enter the 2004 race for the White House as an independent candidate.

A formal announcement by Nader is expected this weekend.

"He's felt there is a role for an independent candidate to play," Linda Schade, a spokeswoman for Nader's presidential exploratory committee.

The relationship between Nader and the Green Party (search) has not been smooth in recent years. Money and ballot access continue to be Nader's main concerns as he's mulled a run this year.

The Associated Press contributed to this report.