Lieberman: McCain's Ayers ad fair

WASHINGTON, Oct. 5 (UPI) -- Republican U.S. presidential nominee John McCain's camp has the right to question Democrat Barack Obama's ties to an ex-radical, Sen. Joe Lieberman said Sunday.

The Connecticut independent, who has endorsed McCain, said it is fair to question Obama's association with former Weather Underground leader William Ayers, now a college professor.

"Well, it is fair game," Lieberman, the 2000 Democratic vice presidential nominee, said in an appearance on "Fox News Sunday."

Missouri Sen. Claire McCaskill, an Obama supporter, criticized the McCain ad raising questions about Obama's relationship with Ayers, saying voters deserve better than hit pieces. She said Obama was a child when Ayers was part of the Weather Underground.

"American people deserve so much better," she said. "Do they really think America's going to think that Barack Obama is palling around with terrorists? What that man did, Barack Obama has condemned. And by the way, he did it when Barack Obama was 8 years old. Come on."