Democrat John Edwards (search), determined to cut into John Kerry's (search) advantage, said he intends to use Thursday's televised debate to draw clear differences with the front-runner on trade and other issues.

Declaring that he was "very much in this for the long haul," Edwards told reporters that the debate — the first since Howard Dean's (search) withdrawal turned the battle into a two-way race among the major contenders — was "an important opportunity for both of us."

Edwards hoped a strong debate performance might help fuel a late surge in support heading toward a 10-state Democratic presidential showdown, while Kerry was seeking to further solidify his dominance as front-runner.

But the North Carolina senator's advisers agreed that narrowing the gap with his Senate colleague from Massachusetts would be difficult, especially in California, where Kerry enjoys more than a 2-to-1 advantage in recent polls.

"We have a mountain to climb," said Herb Wesson, former state assembly leader and California chairman of Edwards' campaign. "But we have just elected a governor who is an actor. So nothing's impossible in this state."

Edwards' strategy is to win Ohio, Minnesota and Georgia and gain a healthy share of delegates in New York and California. That would be enough, his advisers believe, to propel him to March 9, where he needs to sweep the four Southern states to set up a showdown March 16 in Illinois. The advisers know the odds are long.

The two rivals were facing off in a debate in Los Angeles, the first since the field narrowed last week with Dean's departure after a disappointing finish in the Wisconsin primary.

The 90-minute evening debate at the University of Southern California will include trailing contenders Dennis Kucinich (search) and Al Sharpton (search).

Both Kerry and Edwards had a relatively light schedule Thursday to give them time for debate preparation.

Edwards picked up endorsements Thursday from California Senate President Pro Tem John Burton and ACORN, an advocacy organization for low- and moderate-income families.

Kerry, meanwhile, received the endorsement of The New York Times in an editorial published Thursday. He planned to join striking grocery workers on the picket line in Santa Monica before the debate — one of two debates before next week's Super Tuesday contests. The other is Sunday in New York City.

A state poll showed Edwards badly trailing Kerry in California. Kerry also held commanding leads in other key Super Tuesday states, including Ohio and New York.

Of the 10 contests, Edwards appeared most competitive in Georgia, where a poll had him 8 percentage points behind Kerry.

Kerry so far has won 18 Democratic contests while Edwards has won one, South Carolina, where he was born.

Both Kerry and Edwards courted Dean supporters. Campaigning in three California cities on Wednesday, Edwards called the former Vermont governor "my friend" and "a powerful voice for change."

Edwards' advisers conceded his challenge was a long shot, but they said the one-term senator and former trial lawyer's optimism and upbeat message have won over audiences, and that Thursday's debate could give cable television viewers in key primary states a chance to know him better.

"We're not running against Kerry, we're running against time," said David Axelrod, an Edwards media consultant.

Edwards himself said Wednesday that he hopes in California and other key Super Tuesday states the same late-developing "powerful response and surge" that led to his strong second-place finish last week in Wisconsin.

In Washington on Wednesday, GOP chairman Ed Gillespie criticized Kerry's 19-year Senate voting record, citing his votes for anti-terrorism legislation, an education measure and a free-trade pact, and his subsequent criticism of the Bush administration.

"There are any number of things where Senator Kerry has gone back and forth on issues and raised a credibility question," Gillespie said.

In response, Kerry's campaign arranged a conference call for reporters with former Georgia Sen. Max Cleland and Rep. Norm Dicks, D-Wash., a senior member of the House Appropriations Defense subcommittee, who defended Kerry.

"Give me a commander in chief who's going to have some skepticism about certain programs if they're not working," Dicks said.