May 9, 2008 -- Sen. John McCain, R-Ariz., faces enormous pressure from social conservatives to ignore his repeated commitment to change the GOP's platform on abortion.

"If he were to change the party platform," to account for exceptions such as rape, incest or risk to the mother's life, "I think that would be political suicide," said Tony Perkins, the president of the conservative Family Research Council, to ABC News. "I think he would be aborting his own campaign because that is such a critical issue to so many Republican voters and the Republican brand is already in trouble."

A senior Republican close to McCain told ABC News that building a more inclusive GOP is a top priority for the Arizona senator.

But this adviser does not see changing the party platform to include exceptions for rape, incest, and the life of the mother as necessary for achieving that vision.

The problem for McCain, however, is that he excoriated then-Gov. George W. Bush during a 2000 debate for not being willing to make this change to the platform, and Democrats are salivating at the prospect of arguing, in the words of one strategist, "that another four years of Bush begins with another four years of Bush's platform."

Watch McCain's heated exchange with Bush here.

McCain Reaffirmed Position in 2007

While McCain has not addressed the abortion platform since becoming the presumed Republican nominee, he reaffirmed his desire to change the GOP's official abortion stance following a multicandidate forum that took place in Des Moines, Iowa, April 14, 2007.

Despite McCain's support for changing the platform in 2000 and 2007, Sen. Sam Brownback, R-Kan., the co-chairman of McCain's Justice Advisory Committee, significantly downplays the possibility that McCain would revise the party's call for a nationwide constitutional ban on abortion with no exceptions.

"I don't think that's going to happen. I think you're going to see a platform process that is going to maintain that plank," said Brownback, a leading abortion rights opponent who endorsed McCain after ending his own White House bid.

"There are going to be a number of people supporting his nomination that want that plank left exactly as it is," he said. "They're going to be a strong majority."

The GOP's platform committee will meet in Minneapolis-St. Paul the week before the Sept. 1-4 Republican National Convention.

Winning Conservatives, Alienating Moderates?

While leaving the platform untouched would please many in the GOP's socially conservative base, it could alienate some of the more moderate voters that McCain hopes to woo.

"If he doesn't change the platform, then he's being the same kind of hypocrite that he accused Bush of being in 2000," said Jennifer Blei Stockman, the co-chairwoman of Republican Majority for Choice. "To not accept abortion in cases of rape and incest, give me a break. That's sick. That's inhumane."

"And the life of the mother?" she added. "These are things that we can't even put our arms around because they are so inhumane."

Brownback defended McCain against the prospect of being called a flip-flopper.

"I don't know how you can accuse John McCain of being a flip-flop on a topic where the party rank and file that will be at the convention will support that plank even if his views differ slightly," said Brownback. "Newt Gingrich had the right statement: It's a pro-life party with a pro-choice wing."

Stockman said that McCain's team is ignoring his previous commitments on this issue and is intentionally downplaying his clout.

"If McCain chooses not to revise the platform, I think he will say it's 'the system' and he will try to distance himself from it," said Stockman. "But he absolutely has the power to change it."

"Many people think of him as a moderate," she said. "But when it comes out that he doesn't want to change this extreme, right-wing Republican platform, the word 'moderate' is going to disappear from any description of McCain."

ABC News' Talal Al-Khatib contributed to this report.