Former Massachusetts governor Romney dropped out of the race on Thursday, making Arizona senator John McCain a virtual sure thing for the GOP nomination.
Romneys withdrawal was announced at a Conservative Political Action Committee luncheon in Washington.
Excerpts from his statement: "I must now stand aside, for our party and our country. If I fight on in my campaign, all the way to the convention, I would forestall the launch of a national campaign and make it more likely that Senator Clinton or Obama would win.
"And in this time of war, I simply cannot let my campaign be a part of aiding a surrender to terror .
"This is not an easy decision for me. I hate to lose. My family, my friends and our supporters... many of you right here in this room... have given a great deal to get me where I have a shot at becoming President. If this were only about me, I would go on. But I entered this race because I love America, and because I love America, in this time of war, I feel I now have to stand aside, for our party and for our country."
The wealthy former business magnate, who has a personal fortune estimated at between $250 million and $500 million, may have spent as much as $50 million of that on a race that he launched last year in expectation of winning some key early states. His losses to Huckabee in Iowa and McCain in New Hampshire, though, were never offset by enough wins elsewhere to keep his candidacy viable.