When the predominantly conservative Republican faithful descend on Manhattan this summer to officially renominate President Bush, the four-day convention’s biggest draws may not be the vice president or even the president.

That distinction could belong to a socially liberal movie star and a former New York mayor who signed into law legislation creating domestic partnership rights for gays: California Gov. Arnold Schwarzenegger and Rudy Giuliani.

“They’ll probably steal the show in New York,” possibly even “upstaging Cheney and Bush themselves,” said Stephen Moore, president of the conservative Club for Growth.

But Republicans across the ideological spectrum appear unconcerned that many of the social views of their party’s highest-profile celebrities would seem more at home in the Party of Jackson than Lincoln, and they point to such policy divergences as yet another example of the “big tent” nature of the GOP.

“In these two men’s cases they appeal to certain voters on a social level more so than other Republicans,” said Republican National Committee spokeswoman Mary Ellen Grant. “A lot of people are giving the Republican Party a second look as a result of their involvement.”

Some Republicans see Giuliani and Schwarzenegger’s popularity as a sign of their party’s maturation.

“This is what it takes to maintain a majority status,” said California Republican strategist Dan Schnur matter-of-factly. “Just because there is room for a blue-state moderate doesn’t mean that the party’s base will not remain red-state conservative.”

New York consultant David Garth, who helped run Giuliani’s first campaign, said “the Democratic Party has heavier support on the left than the Republican Party has [from the right] comparatively speaking.” This is why candidates like Giuliani and Schwarzenegger can still flourish in the GOP despite some disagreements on social policy. No parallel dynamic exists in the Democratic Party, said Garth, who has advised Democrats and liberal Republicans in his 40-year career.

In California, where prior to last October’s gubernatorial recall election the party was in the midst of an extended funk, Schwarzenegger has “made it cool again to be a Republican,” gushed Todd Harris, a consultant to Schwarzenegger and the former body builder’s campaign spokesman.

Nowhere is this appeal more apparent than in the dramatic uptick in funds raised by the California Republican Party since Schwarzenegger seized the reins of power in Sacramento. From October 2003 to February 2004, the state party raked in about $12.2 million, a nearly nine-fold jump over the roughly $1.4 million raised in that same time period in the previous year. In the second half of 2003 alone, 250,000 Republicans were added to the state’s voter rolls.

Golden State Republicans are hardly blind to the source of their good fortune. The state party’s Web site home page is dominated by images of what Communications Director Karen Hanretty dubbed “the major force” in both the party and state. Although Hanretty asserted that Schwarzenegger’s social views — which favor abortion rights, affirmative action and gay rights — would hardly “transform the social viewpoint of the base of the party,” she said that in states like California “it’s about focusing on issues that help us win,” namely the economy.

Moore, who serves on Schwarzenegger’s budget audit team, said that Giuliani and Schwarzenegger’s success underscored the notion that “the one hereditary gene of the Republican Party is … economic conservatism.”

But while the two men’s stances may be in line with New York and California’s more liberal electorates, observers are undecided about the effect either man could have on the party were he to seek national office.

Ultimately, Giuliani’s views — given the very real possibility he will run for president in 2008 — wield the potentially greater impact. (The Austrian-born Schwarzenegger has expressed support for amending the Constitution to allow foreign-born citizens to run for the presidency, but for now he is ineligible for the office.)

“Giuliani is the most formidable candidate that the Republicans have,” said Garth. “I think he’s more formidable than Bush.”

But Giuliani’s pro-abortion rights, pro-gay rights stances “put him beyond the ken of the evangelical wing of the Republican Party,” according to Village Voice Senior Editor Wayne Barrett, author of the 2000 book “Rudy: An Investigative Biography of Rudolph Giuliani.” “If it comes to a Republican convention where he may be nominated, we could see a third to a half of the party walk out. … When was the last time they nominated people for either spot that wasn’t pro-life?”

However, New York political consultant George Arzt, who has advised Giuliani in the past, said that “there might be a way to tinker with his stance” on abortion. The Republican electorate, he said, would unite behind the man — who once said he thought all mayors should be elected on a nonpartisan basis — “if they thought he was a winner.”

GOP candidates across the country appear to have already answered at least part of that question for themselves, and it is overwhelmingly in the affirmative. In the two-plus years since term limits forced Giuliani to give up the mayoralty, he has stumped or raised money for at least 60 Congressional and gubernatorial candidates.

“We did 13 states in three days right before the 2002 election,” said Tony Carbonetti, who was Giuliani’s City Hall chief of staff and now oversees the former Time Person of the Year’s political work from his perch as a partner at Giuliani’s New York consulting firm.

While Giuliani’s endorsements have included all strains of the Republican Party from the conservative Sen. Saxby Chambliss (Ga.) to moderates like Rep. Jim Leach (Iowa) and Schwarzenegger, Carbonetti said ideology did matter “if a person is unknown to him and that’s all you have to go on.”

For its part, Bush-Cheney ’04 has already made ample use of Giuliani, who has stumped for the ticket in Iowa and New Hampshire and appeared at a number of events for the president, including a Long Island fundraiser with Bush earlier this month that brought in $1.6 million.

“We will be doing everything we can to help [them],” Carbonetti said.

As for Schwarzenegger, it’s still unclear how much he’ll do for the party or Bush-Cheney ’04. While Schwarzenegger has said he believes Bush could carry California this year, he has also said the Golden State’s support could be predicated on the federal dollars Bush is willing to channel its way.

While “the governor is committed to the president and the president’s re-election … it’s a little early to talk about schedule,” said Harris when asked whether Schwarzenegger would be stumping for Bush.

“His first, second and third priority is managing the state of California, and that’s always going to take precedence,” Harris added.

Still, that hasn’t stopped fellow GOPers across the country from clamoring for an appearance with the “Governator.”

“We’ve received requests from virtually every Republican governor in the country to campaign or raise money,” said Harris, who noted that Schwarzenegger’s non-California-related activity has been largely limited to a $500,000 fundraiser for the New York County Republican Committee in late February.

Within California, the trio of candidates Schwarzenegger endorsed in the March 2 GOP primary — former Golden State Secretary of State Bill Jones for Senate, Rep. Dana Rohrabacher for re-election, and John Campbell for state Senate — all triumphed in their respective primaries. And all three men are viewed as conservatives.

Ultimately, when it comes down to it, it’s hard for the party to argue with success, said Moore.

“People have admiration for politicians able to pull off stunning political miracles,” he said. “What happened in both cases is you had liberalism run amok … things got so terrible that … voters voted for the fiscally conservative Republican.”