SIMI VALLEY, Calif. - With Democrat John Edwards and Republican Rudolph Giuliani retreating to the sidelines, the presidential nomination battles narrowed to a pair of head-to-head contests yesterday as the remaining candidates dug in for five days of intensive campaigning before a critical Super Tuesday showdown next week.
Mr. Giuliani, who led the national Republican polls for much of last year only to see his support plummet in the opening weeks of the primary-caucus season, folded his campaign and immediately endorsed Sen. John McCain of Arizona at a joint press conference here.
Mr. Giuliani praised Mr. McCain as "an American hero" and "the most qualified candidate to be the next commander in chief of the United States." Today, Mr. McCain expected another boost, an endorsement from California Gov. Arnold Schwarzenegger six days before that state's primary.
Mr. Edwards, whose angry populism and focus on poverty made him a distinctive voice in the Democratic race, ended his candidacy where it began, in the Ninth Ward in New Orleans.
"It is time for me to step aside so history can blaze its path," Mr. Edwards told supporters. He did not endorse either of his two Democratic rivals - Sen. Hillary Clinton of New York or Sen. Barack Obama of Illinois - but said he had asked them to continue drawing attention to the primary themes of his campaign.
"They have both pledged to me - and more importantly, through me to America - that they will make ending poverty central to their campaign for the presidency," he said.
Mr. Edwards' departure left Mrs. Clinton and Mr. Obama facing a potentially protracted contest that could extend past Super Tuesday. The two Democrats will meet for their first one-on-one debate in Los Angeles tonight.
The Republican race could reach an effective conclusion in Tuesday's balloting, with Mr. McCain, coming off his victory in Florida on Tuesday, determined to close out the challenge from former Massachusetts governor Mitt Romney.
Two other Republicans remain in the race: Mike Huckabee, former governor of Arkansas, and Rep. Ron Paul of Texas. But it is primarily a showdown between Mr. McCain and Mr. Romney.
While both the Democratic and the Republican races are now essentially two-person contests, their political contours are markedly different. Mrs. Clinton and Mr. Obama are in a frequently nasty personal fight, but not one that reflects deep ideological divisions or, as yet, threatens to leave the party badly divided once it is over.
Republicans see the prospect of a clear fracture in their coalition as a result of the nomination contest. Mr. McCain is winning important primaries but without support of the party's conservative or religious base.
The remaining candidates face the complex challenge of campaigning across the country in the run-up to the voting on Tuesday in more than 20 states, including California, New York, and Illinois.
As the Republicans gathered in Simi Valley for their second debate of the campaign at the Ronald Reagan Presidential Library, Mrs. Clinton and Mr. Obama hop-scotched across the Feb. 5 landscape on their way to their own forum today.
Mr. Obama praised Mr. Edwards and his wife, Elizabeth: "John has spent a lifetime fighting to give a voice to the voiceless and hope for the struggling," he told 9,000 in the University of Denver basketball arena.
Mrs. Clinton campaigned yesterday in Arkansas and Georgia, focusing on African-American voters. She thanked Mr. Edwards and his wife "for their years of public service."
The question of an Edwards endorsement coursed through the Democratic campaign in the hours after word of his decision became public.
Some experts assumed Mr. Edwards would favor Mr. Obama, the other candidate calling for major change in Washington. But Democrats close to Mr. Edwards cautioned the choice may not be so evident or easy. Mr. Edwards has come to know both candidates through joint appearances over the last year and sees strengths and weaknesses in both, according to Democrats close to the former senator.
In the GOP race, Mr. McCain and Mr. Giuliani are natural allies and the former mayor's endorsement was no surprise.
Mr. Giuliani will help Mr. McCain nail down victories in primaries in the northeast - New York, New Jersey, Connecticut, and Delaware - and their big baskets of delegates. But he will do little to help Mr. McCain bridge the divide within the GOP coalition that now exists.34.28946 -118.7177