Conservative activists are preparing to do battle with allies of Sen. John McCain in advance of September’s Republican National Convention, hoping to prevent his views on global warming, immigration, stem cell research and campaign finance from becoming enshrined in the party’s official declaration of principles.

McCain has not yet signaled the changes he plans to make in the GOP platform, but many conservatives say they fear wholesale revisions could emerge as candidate McCain seeks to put his stamp on a document that currently reflects the policies and principles of President Bush.

A platform fight at the convention could disrupt that carefully choreographed effort by highlighting the stark differences in vision for the party separating McCain from some of the GOP’s most dedicated activists.

The battle may not be avoidable. The current GOP platform is a 100-page document, and all but nine pages mention Bush’s name. Virtually the entire platform will have to be rewritten to lessen the imprint of the president, who has the highest disapproval rating of any White House occupant since Richard M. Nixon.

McCain is “really out of step with the strong majority of his party,” said Myron Ebell, director of energy and global warming policy at the Competitive Enterprise Institute, which opposes McCain’s positions on climate change. “He might get what he wants. And he might get a change. But I don’t think it’s going to sit well with a lot of Republicans.”

Officials in the Republican National Committee and in McCain’s campaign say they have much in common with conservatives. They say their conversations as they approach the convention suggest there will not be a nasty platform fight.

McCain will have to make peace with the conservatives, the hard core ones, if he is to get the totally support that he will need to be the president elect.