This dispatch is from Martha T. Moore of USA Today:

One day after the Florida primaries, the field of presidential candidates was on the verge of shrinking Wednesday, with John Edwards planning to drop out of the Democratic race and Rudy Giuliani mulling his GOP bid.

Edwards planned to make the announcement at a 1 p.m. ET event in New Orleans, a source within the Edwards campaign with direct knowledge of the candidate’s plans confirmed. The Associated Press, which first reported the Edwards decision, reported earlier that Giuliani will drop out today and endorse John McCain, who won Tuesday’s Florida GOP primary.

Giuliani did not deny the endorsement and insisted he was flying to California today ahead of the scheduled GOP debate at the Ronald Reagan Presidential Library. But while addressing supporters Tuesday night, he spoke of his campaign mostly in the past tense.

“Elections are about a lot more than just candidates. Elections are about fighting for a cause larger than ourselves,” Giuliani said.

McCain’s win completed an improbable journey from written-off candidate to front-runner. The Arizona senator’s third win in the four primaries so far, political analysts say, makes him the favorite for the nomination as the candidates head into a 22-state national primary on Feb. 5.

Former Massachusetts governor Mitt Romney had the most at stake in Florida from a momentum standpoint. He has delegates from wins in the Michigan primary and the Wyoming and Nevada caucuses, and his deep pockets — a legacy of his years as a venture capitalist — will allow him to keep fighting.

“It’s not completely over, so long as Romney has a big bank account,” said former House GOP aide John Pitney, a political scientist at Claremont McKenna College. But he said McCain will be difficult to stop.

Though McCain’s campaign was broke and in disarray last year, he returned to the underdog approach he used in 2000 and, town meeting by town meeting, scrapped his way back into contention.

A huge win among Hispanic voters, the collapse of former New York City mayor Giuliani’s campaign and late support from GOP officeholders helped him in Florida. Endorsements from Sen. Mel Martinez and Gov. Charlie Crist “certainly send a signal to Republicans in many other states that some established big-name people are finally getting on the McCain bandwagon,” said Aubrey Jewitt, a political scientist at the University of Central Florida in Orlando.

National party strategist Alex Vogel, who is neutral in the race, said McCain had a “seemingly insurmountable lead” in California polls and was strong in New York, New Jersey and other Feb. 5 states even before Tuesday. The Florida win makes him “virtually impossible to beat,” he said.

McCain, who earlier won New Hampshire and South Carolina, played down such talk. “It’s a very significant boost, but I think we’ve got a tough week ahead and a lot of states to come,” he told the Associated Press.

Giuliani staked his candidacy on Florida. Former Arkansas governor Mike Huckabee said he would fight on, but he is poorly financed and hasn’t notched a win since Iowa.

New York Sen. Hillary Rodham Clinton easily won the Democratic race, a beauty contest with no delegates and no campaigning by candidates. They agreed to a boycott after Florida moved to Jan. 29 in violation of national party rules designed to protect early contests.

Because of that, and because Edwards repeatedly had said he would continue to press his campaign, his decision was a greater surprise.

About 3 million Democrats cast ballots for a turnout of 30%, higher than in the 2000 and 2004 primaries but well below the record 58% in 1972.

A survey of 1,270 Florida Republicans as they left the polls and 235 people who had voted early showed a Republican electorate torn between McCain, a maverick who has alienated some Republicans with his stands on immigration, global warming and campaign spending limits; and Romney, whose positions on guns, abortion, stem cell research and gay rights evolved and became more acceptable to social conservatives.