Agence France-Presse . Washington

Senator John McCain is fighting for the backing of his foes in the Republican Partys conservative base, now that rival Mitt Romney has quit the race, clearing his path to the White House.

Addressing an annual gathering of fervent Republican activists, McCain sought to shore up his conservative credentials and allay fears over his stand on some key issues, as he seeks the partys presidential nomination.

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

With former Massachusetts governor Romney dropping out of the race on Thursday after a slew of poor Super Tuesday showings, McCains path to the Republican ticket is suddenly a lot clearer.

But recognising the crucial support he needs from the partys conservative base to win the nomination for the November elections, the Vietnam war veteran called for its backing in defeating the Democrats.

I am acutely aware that I cannot succeed in that endeavour, nor can our party prevail over the challenge we will face ... without the support of dedicated conservatives, McCain told the Conservative Political Action Conference Thursday at an annual meeting in Washington.

Peppering his speech with references to former president and Republican icon Ronald Reagan, McCain set out a platform of tough stands on various issues from abortion to tax cuts and his unwavering support for the Iraq war.

The Arizona senator, 71, has a solid conservative voting record, but has enraged the key constituency with his campaign finance measures, his stand on immigration reform and his initial opposition to Bushs huge tax cuts. He was only interrupted with boos once, when he brought up his bid to overhaul immigration laws, an issue branded an amnesty by many furious conservative critics. But addressing the immigration issue head-on, McCain told the conference that he had stood my ground aware that my position would imperil my campaign.

His intention had been to restore border controls, he said, vowing that as president he would work first to secure the frontiers before trying to tackle illegal immigration.

I will not obscure my positions from voters who I fear might not share them. I will stand on my convictions, my conservative convictions and trust in the good sense of the voters, McCain said. And he pledged to offer voters a clearly conservative approach to governing, as the crowd warmed to his speech after an initially chilly welcome.

He garnered a standing ovation and chants of John McCain when he vowed no retreat from Iraq. Romney earlier quit the White House race after spending millions of dollars of his personal fortune on a campaign which failed to fire up the party faithful.

This isnt an easy decision, I hate to lose, Romney told the conservative conference, saying he was suspending his campaign to avoid a damaging, divisive race that could hand the November elections to the Democrats. In the deadlocked Democratic race, Barack Obama has reaped seven million dollars since the Super Tuesday clash, amid news that Hillary Clinton faced a cash crunch forcing her to loan her campaign five million dollars.

The former first lady has brought in at least six million dollars since the polls closed Super Tuesday. The Democratic rivals are set for a clutch of smaller primary and caucus contests, before the next big showdowns on March 4 in Ohio and Texas. If no clear winner emerges by then, eyes will turn to Pennsylvanias late April primary, with chances growing the tie may only be broken at the Democratic convention in August.

Obamas campaign announced that he had agreed to two debates ahead of the March 4 vote in order to provide the largest number of voters in upcoming primaries the chance to compare the candidates one-on-one.

McCain won nine of 21 states on offer Tuesday, giving him 724 delegates to the Republican convention. Romney holds onto the 281 he has won so far, while Baptist preacher Mike Huckabee has 196. A total of 1,191 are needed to win the nomination.

Senator Hillary won eight states Tuesday, including the four biggest prizes California, New Jersey, Massachusetts and her home state of New York but Obama won 13.\A Real Clear Politics running count had the New York senator with 1,076 delegates, more than half the 2,025 she needs to capture the nomination. Obama had 1004.