"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.