WASHINGTON — Mayor Giuliani’s bid to win over social conservatives is getting a boost with the endorsement of a leading evangelist, Pat Robertson.

The founder of the Christian Broadcasting Network and a longtime leader of the Christian right, Mr. Robertson announced his support at a Washington press conference yesterday, citing Mr. Giuliani’s stewardship of New York City and his strong stance against terrorism.

“To me, the overriding issue before the American people is the defense of our population from the bloodlust of Islamic terrorists,” Mr. Robertson said.

His backing comes as Senator Brownback of Kansas, who dropped out of the Republican presidential race last month, yesterday threw his support behind Senator McCain of Arizona. The moves underscore the degree to which prominent social conservatives are splitting their support among the top Republicans.

Earlier this week, another leading member of the movement and the co-founder of the Moral Majority, Paul Weyrich, endorsed Mitt Romney, spurring talk that evangelical Christians were about to coalesce around the former Massachusetts governor’s candidacy. With Mr. Robertson’s endorsement of Mr. Giuliani, that speculation will likely dim.

The candidate hurt the most by the flurry of social conservative endorsements is Fred Thompson, who at one time appeared on the cusp of becoming the consensus choice for Republicans disenchanted by Messrs. Giuliani, McCain, and Romney. But his campaign has struggled to generate excitement.

Mr. Giuliani, whose support of abortion and gay rights has been well documented, spoke at Mr. Robertson’s Regent University in June, and the two have talked about sharing a bond as survivors of prostate cancer.

Those personal ties mitigate the level of shock at an endorsement from a conservative leader so staunchly opposed to abortion.
“The announcement does not come as a surprise,” the dean of Regent’s Robertson School of Government, Charles Dunn, said. “Their relationship goes back some time.”

Mr. Dunn described the move as a “win-win” for both Mr. Giuliani and Mr. Robertson. The former mayor, he said, “needed a whale of the evangelical movement to endorse him” to slow down Mr. Romney’s momentum with social conservatives. “This is a big whale,” Mr. Dunn said. And as for Mr. Robertson, endorsing Mr. Giuliani “makes him a big player in the game,” Mr. Dunn said.

The former mayor has tried to cast himself as the Republican with the best chance at defeating the Democratic front-runner, Senator Clinton, but Mr. Robertson said his choice was “not a calculated decision” about electability. Rather, he said, it was about security. “America must be kept safe,” Mr. Robertson said.

For Mr. Giuliani, the endorsement will help him in the Republican primary, but it is not without risk. Mr. Robertson has drawn the ire of an array of interest groups in recent years with outlandish statements that have angered women, homosexuals, and Jews, among others.

Shortly after the terrorist attacks of September 11, 2001, he appeared to agree with the comments of another prominent evangelist, Jerry Falwell, who blamed the attacks on “the pagans, and the abortionists, and the feminists, and the gays and the lesbians who are actively trying to make that an alternative lifestyle, the ACLU, People for the American Way.”

In 2005, he was forced to retreat from a remark suggesting that the president of Venezuela, Hugo Chavez, be assassinated. “I don’t know about this doctrine of assassination, but if he thinks we’re trying to assassinate him, I think that we really ought to go ahead and do it,” Mr. Robertson said on a broadcast of “The 700 Club.”

And last year, Mr. Robertson suggested that Prime Minister Sharon’s stroke had been punishment from God for his willingness to give up land to the Palestinian Arabs. Jewish groups were infuriated, and the remark drew a rebuke from the White House before Mr. Robertson apologized.

He has also criticized Islam as a violent religion, going much further than many American politicians, who are careful to distinguish between “Islamic extremists” and a majority of Muslims who are peaceful.

Asked for comment about Mr. Robertson’s various controversies, a spokeswoman for the Giuliani campaign, Maria Comella, said: “There are areas of difference between the two, but shared goals.”

Mr. Giuliani has also courted Mr. Brownback’s endorsement, but if the abortion issue did not figure prominently in Mr. Robertson’s decision, it did for the Kansas senator. In throwing his support to Mr. McCain, Mr. Brownback said the Arizona Republican was “the best pro-life candidate to beat Hillary Clinton” and in a statement he cited Mr. McCain’s “consistent 24-year pro-life record of protecting the rights of the unborn.”