Rivals take aim with sharpened messages

"This is a man who endured great adversity yet remained loyal to this nation," Quinn said.

"We need heroes like this," he added.

The crowd roared. But the mood turned angry when McCain and Palin spooled out the arguments against Obama they had made earlier in the day in Pennsylvania.

"Liar!" someone yelled, in reference to the Democratic nominee.

In their two campaign stops, neither McCain nor Palin mentioned Obama's past association with William Ayers, the 1960s-era radical Weather Underground founder.

But in an interview with Fox News, Palin cited Ayers as reason to question Obama's "judgment."

Palin told Fox's Sean Hannity, in a transcript provided by the network: "And -- not only those terrorist activities that Bill Ayers was involved in, but the questions need to be asked, I believe, when did Barack Obama know of these activities? We've heard so many confliction stories and flip-flop answers about when he knew the guy, did he realize that he knocked off his political career in the guy's living room?"

A recent article about Ayers in the New York Times said the two men were not close.

With the race winding down and McCain trailing in the polls, the Republican ticket has gotten more personal in its attacks. An independent study by the Wisconsin Advertising Project showed that in the week of Sept. 28 to Oct. 4, nearly all of the McCain campaign's ads were negative. In contrast, the group rated 34% of Obama's ads during that time frame as negative.

McCain's advisors said that the criticism of Obama is legitimate and that their candidate is merely raising questions about whether someone so new to the national scene should be elevated to the White House.

McCain's message was that Obama would be a poor choice for president on two fronts: His policies are wrong, and his word is suspect.

"We have all heard what he has said, but it is less clear what he has done or what he will do," McCain said in Pennsylvania.

At that, the crowd broke into a chant of "No-Bama! No-Bama!"

McCain continued: "You know, what Sen. Obama says today and what he has done in the past are often two different things."

He said that Obama had once called the subprime loans that have fueled the housing foreclosure crisis "a good idea."

"Well, Sen. Obama," McCain said, "that 'good idea' has now plunged this country into the worst financial crisis since the Great Depression."