Former Massachusetts Gov. Mitt Romney ended his Republican presidential bid Thursday, acknowledging that he didn't want to split the party by helping the political opposition during the war on terror, calling it the campaign's key issue.
Romney, 60, a favorite among many conservatives partly because of his business acumen, said he would continue to fight for the principles that shaped his campaign, but that the greatest challenge facing "the entire civilized world (is) the threat of violent, radical Jihad" and he could not fight on to the Republican National Convention because "we are a nation at war."
His withdrawal from the race, during a speech to the Conservative Political Action Conference in Washington, all but secures the nomination for Sen. John McCain of Arizona.
McCain needs 1,191 delegates to win at September's convention in St. Paul, Minn. He won 707 delegates in primaries and caucuses through Super Tuesday, compared to Romney's 294 and 195 for former Arkansas Gov. Mike Huckabee, according to a tally by The Associated Press.
Romney gave a tepid endorsement of McCain in his speech, saying he disagrees with McCain on a number of issues but "I agree with him on doing whatever it takes to be successful in Iraq ... and on eliminating al-Qaida and terror."
Continuing a contested GOP race could make it more likely that Democrat Sens. Hillary Clinton or Barack Obama might win, he said, and "they would retreat and declare defeat" in Iraq.
"In this time of war, I simply cannot let my campaign be a part of aiding a surrender to terror," Romney said, acknowledging the decision to quit was difficult. "If this were only about me, I would go on. But I entered this race because I love America, and because I love America I feel I must now stand aside, for our party and for our country."
Romney said Americans must fight to preserve the culture of hard work, education and opportunity that made the United States the most powerful nation in history. The country's prosperity, security and future are threatened, he said.
"I am convinced that unless America changes course, we will become the France of the 21st century -- still a great nation, but no longer the leader of the world, no longer the superpower," he said. "And to me, that is unthinkable."
McCain, 71, promised to uphold conservative principles in a speech that followed Romney's to a skeptical audience at the conference.
"I am proud to be a conservative," he said. "You need not examine only my past votes and speeches to assure yourselves that they are my genuine convictions. You can take added confidence from the positions I have defended during this campaign."
Former Sen. Rick Santorum, who had endorsed Romney, said he would be willing to meet with McCain to help him build trust with the party's conservatives.
"I would absolutely sit down with him; that is my responsibility," Santorum said. "He needs to lay out his principles -- 'Here is what I, John McCain, believe in, here is what motivates me, here is what I care about.' "
Until now, conservatives were split, some favoring Romney's emphasis on the economy and ecumenical’s favoring Huckabee.
Billing himself as an "authentic, consistent conservative," Huckabee issued a statement saying he does not intend to end his campaign.
"This is a two-man race for the nomination, and I am committed to marching on," he said. "I believe in the importance of a strong national defense -- which includes winning the war against Islamic extremists and the protection of American sovereignty."
Former House Majority Leader Tom DeLay, who runs the nonprofit New Coalition for a Conservative Majority, said he would meet with McCain, if McCain contacts him. DeLay said he remains uncommitted, but "now the race is over and John McCain is the nominee."
"He should be the one to reach out," DeLay said.
Former Pennsylvania Gov. Tom Ridge, a McCain supporter, said Romney's focus on economic issues "sharpened the focus of all the Republican candidates." Ridge said he thinks McCain understands the importance of unifying the party, in order to ensure a Republican victory in November.
"I hope conservatives are as open to his outreach as he is aggressive to them," Ridge said.
Brian Schaffner, an assistant professor at American University, said Romney led the field in raising money last year but needed to win early contests -- the Iowa caucus and New Hampshire primary -- in order to have a chance.
"Once he lost those states, it was nearly impossible for him to recover," Schaffner said.
Larry Sabato, a political science professor at the University of Virginia, said McCain needs to mobilize supporters and money for fall.
"It will be a difficult race, under tough conditions, for any Republican," he said.