Mr. McCain’s once easygoing if irreverent campaign presence  endearing to crowds, though often the kind of undisciplined excursions that landed him in the gaffe doghouse  has been put out to pasture. He takes far fewer chances, meaning there are fewer risqué jokes, zingers at a familiar face in the crowd, provocative observations on policy or politics, or exercises in self-derogatory humor. By every appearance, this Mr. McCain is, or at least is struggling to be, disciplined and on message in a way befitting of American politics today, if not quite befitting of the McCain of yesterday.

There may be a price for all this. After his running mate, Gov. Sarah Palin of Alaska, riveted the overflow crowd for 16 minutes on Tuesday at an airplane hangar here, it was Mr. McCain’s turn, and people in his audience began murmuring and drifting away midway through a 14-minute speech that was flat and cheerless. When Mr. McCain made his first appearance without Ms. Palin, on Monday morning in Jacksonville, Fla., he faced an arena that was one-quarter full.

Still, it is the course Mr. McCain has chosen and one his aides say he will stay on.

To a certain extent, Mr. McCain, of Arizona, is grappling with the fact that he is now a general election candidate in an environment where, more than ever, the other side (or reporters who are following him) is ready to seize on any slip-up, real or imagined. This is no time for the idle remark, bout of frankness or edgy humor that once stood Mr. McCain apart on the candidate field.

And what voters are seeing in these final weeks of the campaign is a deliberately retooled version of Mr. McCain  what he says, how he says it and how he goes about the day-to-day steps of campaigning. It came about as part of a fundamental reordering of his campaign that resulted from the ascension of the hard-driving, disciplined Steve Schmidt, a senior campaign adviser and veteran of President Bush’s 2004 campaign, who popped up on Mr. McCain’s plane one day this week.

Mr. McCain is by all appearances struggling to stick to his script and avoiding, whenever possible, events that his campaign cannot control.