Former presidential hopeful Mitt Romney endorsed Republican front-runner John McCain on Thursday, boosting his one-time rival's chances of wooing wary conservatives and unifying the party against the eventual Democratic nominee.
Putting aside their sharp differences, Romney praised the former Vietnam war prisoner as a "true American hero" and urged the 291 delegates pledged to vote for him to switch allegiance to the Arizona senator.
"I am honored today to give my full support to Senator McCain's candidacy for the presidency of the United States," the former Massachusetts governor said in a news conference from his home state's city of Boston.
"And today I'm asking my delegates to vote for Senator McCain at the convention," he said.
Despite emerging as the likely Republican nominee after Romney dropped out of the race last week, McCain has struggled to convince hardcore conservatives suspicious of his views on illegal immigration and taxes.
But Romney said Republicans should rally around McCain and seize on the fact that Democrats Hillary Clinton and Barack Obama were in a close nomination race.
"Right now, the Democrats are fighting," he said. "Let us come together and make progress while they're fighting."
But the big looming question is if Romney's 291 delegates will jump to McCain's side or refuse to back him.
"Now we move forward together for the good of our party and the nation, and I'm honored -- I am very honored to have Governor Romney and the members of his team at my side," McCain said.
"And that's a vital ingredient for victory in November."
While McCain is almost mathematically assured of winning the nomination, ordained Baptist minister Mike Huckabee has remained in the race, as a string of wins in conservative southern states have given him 240 delegates.
McCain has 825 delegates so far, according to independent pollster RealClearPolitics.com. If all of Romney's delegates switch to McCain, the 71-year-old Arizona senator would be just 75 shy of the prized nomination to stand in the November 4 presidential election.
While the Democrats are still waiting for a winner to emerge, they are already campaigning against McCain.
"If you don't think John McCain is just as dangerous in the White House as George W. Bush, think again," warned the Democratic Party Thursday as it launched a fund-raising appeal.
McCain's team has been playing on the Arizona senator's decades of political experience against freshman Senator Obama, with just two years under his belt in the Senate.
"Obama does not have the experience to serve our nation as commander in chief," said Republican Party chairman Mike Duncan.
McCain himself borrowed a line from Clinton, charging that Obama's electrifying speeches lack substance.
"To encourage a country with only rhetoric rather than sound and proven ideas that trust in the strength and courage of free people is not a promise of hope. It is a platitude," said McCain, taking a clear swipe at Obama in a Tuesday victory speech.
Obama has already taken swipes at McCain.
"George Bush may not be on the ballot this fall, but his tax cuts and his economic policies are," he said this week.
"And if John McCain wants to debate the specifics of how well the economy has worked for ordinary families over the last seven years, that is a debate that I am happy to have because the American people know that Bush's policies have not worked for ordinary Americans."
Senator Clinton, meanwhile, finally got a bit of good news Thursday after New Mexico's Democratic Party announced she had narrowly won its caucuses, which were held more than a week ago, on Super Tuesday.
Obama has won eight straight nominating contests since the 22-state votes on February 5, which ended in a deadlock.
The two Democrats are now eyeing the Wisconsin primary on Tuesday before the next key date, March 4, when delegate-rich Texas and Ohio hold nominating contests.
Despite her recent defeats, Clinton's campaign is hopeful she can win in the two big states.
While no recent polls have appeared in Texas, a Quinnipiac University survey out Thursday showed Clinton leading Obama 55 percent to 34 percent in Ohio.
Obama has 1,289 delegates, only narrowly leading Clinton who has 1,237, according to RealClearPolitics.