"This is not the time to turn our back on the progress we've made on the issues that matter most,", the Arizona senator told a gathering of "values voters." Added , in prepared remarks: "We're not going to beat by acting like Hillary Clinton."
Seeking to draw a contrast,highlighted his Senate tenure, saying: "I was a consistent conservative ... That's who I was then, that's who I am today, and that's the kind of president I would be."
Without naming Giuliani, they challenged the candidacy of the former New York mayor, their thrice-married GOP rival who leads in national popularity polls and has sought common ground with social conservatives despite his support for abortion rights and gay rights. Giuliani argues that whether people agree with him or not on the issues, he has the best chance to beat Clinton, the Democratic front-runner.
All the major Republican presidential hopefuls - and most of the lesser-knowns - were speaking to a gathering sponsored by the Family Research Council, a conservative advocacy group. This segment of the party's base has not coalesced around a Republican candidate.
The fact that no candidate has yet locked up the support of this segment of the party's base may be one of the most, reports CBSNews.com's David Miller. In 2000, Christian conservatives were quick to rally around George W. Bush and stuck with him, helping him win two terms in office.
"These are the influencers, these are the talkers," Tony Perkins, president of the Family Research Council, said of the attendees that will take over the Washington Hilton hotel. "This could be when things start to shake out and a candidate begins to emerge with a certain level of support. I don't think anybody's going to walk away with a lock, but maybe one or two candidates, maybe three, will begin to take off with strong support from the base."
According to a new CBS News poll, evangelical voters remain overwhelmingly conservative, but they are largely unsatisfied with the current crop of Republican candidates, who they feel are not discussing their priorities -- not gay marriage and abortion, with which evangelical voters are often identified -- but issues that are also a top priority for voters overall, including the war in Iraq and health care.
Among white evangelical registered voters, 23 percent want to hear presidential candidates discuss health care, while 20 percent want them to talk about the war in Iraq. Both figures are only slightly lower than the overall population of registered voters. Abortion and same-sex marriage were at the bottom of the list for both groups. ()
At the event, Thompson's campaign distributed fliers trumpeting his current anti-abortion rights views and assailing both Giuliani and Romney. Thompson has drawn criticism for conflicting statements on abortion in his Senate races and his lobbying work on behalf of an abortion-rights organization, as well as his opposition to a constitutional amendment banning gay marriage.
"We've been together for a long time," Thompson told the crowd. "We've not always agreed on precisely the right approach to absolutely everything but our goal has always been the same" - to improve the country.
He earned a standing ovation and cheers when he mentioned what he would do in his first hour as president, saying: "I would go into the Oval Office and close the door and pray for the wisdom to know what was right and I would pray for the strength to do what is right."
Last month, Thompson said he was not a regular church-goer, typically attending services when he visited Tennessee but not while he was living in McLean, Va.
On the eve of his address, Thompson also told reporters he had no regrets about the work he did on behalf of National Family Planning and Reproductive Health Association. "That was private life," Thompson said, adding that while in the Senate he opposed abortion rights.
Sen.of Kansas, a favorite of the religious right, received an enthusiastic response from the couple of thousand conference attendees. He made no mention of his .
As he lamented the lack of a consensus candidate for social conservatives, Brownback did, however, say: "I came to them with the cause, but I don't have the resources and the name." (Read more about Brownback's appearance in Horserace.)
McCain, who got a polite reception and a standing ovation, indirectly slapped at Giuliani, Romney and Thompson.
"I'll match my record of defending conservative principles against any other candidate in this race," McCain said, adding that while voters may not always agree with him, "I hope you know I'm not going to con you."
Social conservatives, McCain said, should pick a candidate who has demonstrated a consistent commitment to their values. "I have a record that can be trusted," he said.
That pitch gets to the heart of McCain's woes with this group: It doesn't trust the man who in 2000 called its leaders "agents of intolerance." He also hasn't been a vocal champion of its core issues - even though his voting record on topics like abortion is solidly conservative.
"I have been pro-life my entire public career," McCain said. "I won't ever change my position to fit the politics of the day."
In his own prepared remarks, Romney, whose Mormon faith has made some evangelical Christians wary, implicitly tries to dismiss the notion that his religion is repelling Christian conservatives. He says: "I'm pleased that so many people of many faiths have come to endorse my candidacy and my message."
He also pokes at Giuliani repeatedly. Romney, who ran for governor as a moderate in 2002 but who has shifted to the right as he seeks the presidency, is hoping to emerge as the main alternative to Giuliani.
Setting up a contrast with Giuliani's multiple marriages, Romney says: "I am pro-family on every level, from personal to political." He emphasizes his three-decade-long marriage to one woman, Ann, and talks about their five sons, his daughters-in-law and 10 grandchildren.
As he does often, he talks of "three legs of the Republican stool" - a stronger military, a stronger economy, and stronger families - that unite the three types of conservatives in the party, defense, economic and social.
Romney adds: "We won't win the White House with only two out of three or one out of three" - a clear reference to Giuliani's moderate-to-liberal views on social issues.