After a turbulent week that included disclosures about Gov. Sarah Palin and signs that Senator John McCain was struggling to strike the right tone for his campaign, Republican leaders said Saturday that they were worried Mr. McCain was heading for defeat unless he brought stability to his presidential candidacy and settled on a clear message to counter Senator Barack Obama.

Again and again, party leaders said in interviews that while they still believed that Mr. McCain could win over voters in the next 30 days, they were concerned that he and his advisers seemed to be adrift in dealing with an extraordinarily challenging political battleground and a crisis on Wall Street.

The expressions of concern came after a particularly difficult week for Mr. McCain. On Friday night, new questions arose about his choice of Ms. Palin as his running mate after an investigation by the Alaska Legislature concluded that she had abused her power in trying to orchestrate the firing of her former brother-in-law, a state trooper.

“I think you’re seeing a turning point,” said Saul Anuzis, the Republican chairman in Michigan, where Mr. McCain has decided to stop campaigning. “You’re starting to feel real frustration because we are running out of time. Our message, the campaign’s message, isn’t connecting.”