Mitt Romney quits race

By John Whitesides, Political Correspondent

WASHINGTON (Reuters) - Mitt Romney ended his struggling U.S. presidential bid on Thursday, clearing the way for John McCain to become the all-but-certain Republican nominee and begin mending fences with disgruntled party conservatives.

In an appearance before a conference of conservative activists, Romney said he was ending his bitter nominating duel with McCain to allow Republicans to focus on a November election showdown with the eventual Democratic nominee, either Sen. Hillary Clinton or Sen. Barack Obama.

"I feel I have to now stand aside, for our party and for our country," the former Massachusetts governor told the shocked crowd, some of whom gasped and shouted "no, no" in response.

McCain, who had built an almost insurmountable lead in delegates to the party's nominating convention, pleaded for party unity during an appearance at the same conference a few hours later.

"I know I have a responsibility, if I am, as I hope to be, the Republican nominee for president, to unite the party and prepare for the great contest in November," the Arizona senator told the activists gathered in a Washington hotel.

"And I am acutely aware that I cannot succeed in that endeavor, nor can our party prevail over the challenge we will face from either Senator Clinton or Senator Obama, without the support of dedicated conservatives," he said.

Romney pulled out after losing 14 of 21 states on Tuesday, the biggest day of U.S. presidential voting ahead of November's election, while McCain romped to coast-to-coast wins and cemented his position as front-runner.

Former Arkansas Gov. Mike Huckabee, who won five states on Tuesday, remains in the race but will have an almost impossible task overcoming McCain, who has rolled up more than 700 of the 1,081 delegates needed to win the nomination.