John McCain asks conservatives for support

WASHINGTON (Reuters) - Republican John McCain askeddisgruntled conservatives to support his presidential bid onThursday, shortly after Mitt Romney ended his strugglingcampaign and made McCain the all-but-certain nominee.

McCain assured a conference of conservative activists hewas one of them, citing his commitment to win in Iraq, haltIran's nuclear ambitions and rein in the federal governmentwhile drawing sharp contrasts with potential Democraticopponents Hillary Clinton or Barack Obama.

McCain's speech, which drew boos on the topic of illegalimmigration, followed by a few hours Romney's surpriseannouncement at the conference that he was ending his run toallow Republicans to focus on the November election.

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

McCain, who has built an almost insurmountable lead indelegates to the party's nominating convention, pleaded forparty unity during his appearance at the annual conference.

McCain, the 71-year-old former Vietnam prisoner of war, hasbecome a target of critics on the right for his moderate viewson illegal immigration, his votes against President George W.Bush's tax cuts in 2001 and 2003 and his labelling in 2000 ofsome religious conservative leaders as "agents of intolerance."

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

"And I am acutely aware that I cannot succeed in thatendeavour, nor can our party prevail over the challenge we willface from either Senator Clinton or Senator Obama, without thesupport 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'selection, while McCain romped to coast-to-coast wins andcemented his position as front-runner.

Former Arkansas Gov. Mike Huckabee, who won five states onTuesday, remains in the race but will have a difficult taskovercoming McCain, who has rolled up more than 700 of the 1,081delegates needed to win the nomination.

"This is a two-man race for the nomination, and I amcommitted to marching on," Huckabee said in a statement afterRomney's withdrawal.

McCain's name was booed by some members of the audiencewhen Romney mentioned him, but he drew mostly cheers when heappeared before the crowd -- many of them McCain supportersbrought in by the campaign.

DRAWS SOME BOOS

He earned boos, however, when he brought up his supportduring last year's Senate debate for a path to citizenship forillegal immigrants. McCain has since said border security mustcome first.

"It is my sincere hope that even if you believe I haveoccasionally erred in my reasoning as a fellow conservative,you will still allow that I have, in many ways important to allof us, maintained the record of a conservative," McCain toldthe conference.

Some attendees said they were disappointed Romney wasleaving, calling him the only conservative candidate in therace.

"This leaves me very concerned about the future of theRepublican Party," said Nathan Shapiro, 22, a college studentin New York. "I don't think McCain will carry on the traditionsof the Republican Party, he's not a real conservative."

Romney said he was pulling out of the race in order to letRepublicans prepare for a general election battle against thetwo remaining Democrats, both whom have campaigned to withdrawU.S. troops from Iraq.

"In this time of war, I simply cannot let my campaign be apart of aiding a surrender to terror," he said.

McCain said Obama, an Illinois senator, and Clinton, a NewYork senator, would create a disaster in Iraq, fail torecognize the threat posed by Iran and weaken the fight againstIslamic extremists.

"Their resolve to combat it will be as flawed as theirjudgment," he said.

Clinton and Obama, locked in a tight and costly duel forthe Democratic nomination, both announced new fundraisingachievements and took note of McCain's ascension to the role oflikely nominee.

Clinton, who said on Wednesday she had pumped $5 million(2.6 million pounds) of her own money into the race to keep upwith Obama, raised $4 million online in the day after pollsclosed on Tuesday and a total of $7.5 million in the month,aides said.

Obama raised more than $7 million since polls closed onTuesday, his camp said.

Clinton said she had great respect for McCain but plenty ofpolicy differences.

"I believe that he offers more of the same -- more of thesame economic policies, more of the same military policies inIraq. He said recently he could see have American troops inIraq for 100 years," she said at a rally in Arlington,Virginia.

(To read more about the U.S. political campaign, visitReuters "Tales from the Trail: 2008" online athttp://blogs.reuters.com/trail08/

(Reporting by Steve Holland, Andy Sullivan, DeborahCharles; Editing by Patricia Wilson and David Wiessler)