Delaware's Republican Senate nominee on Sunday made light of a years-old video clip in which she said, "I dabbled into witchcraft."

The Tea Party-backed Christine O'Donnell, who upset longtime Rep. Mike Castle in the state's primary last week, joked Sunday that she made the comments when she was in high school, asking, "How many of you didn't hang out with questionable folks in high school?

"There's been no witchcraft since," O'Donnell noted. "If there was, Karl Rove would be a supporter now."

The video clip surfaced Friday when TV host Bill Maher aired it. The 11-year-old clip was from a previously unaired episode of Maher's old show, "Politically Incorrect."

O'Donnell responded while attending a GOP event in Delaware on Sunday.

Appearing on "Fox News Sunday," Rove said O'Donnell needed to explain the comments to voters. "In southern Delaware, there are a lot of church-going people; they're probably going to want to know, What was that all about?" Rove said.

After traveling to Washington on Friday to speak at the Family Research Council's Values Voter Summit, O'Donnell canceled two Sunday show appearances, which drew fire from the campaign of her Democratic opponent, Chris Coons.

"Ms. O'Donnell has not yet provided a single solution or idea on how to get our economy back on track," Coons spokesman Daniel McElhatton said in a statement. "It is clear that she is simply not prepared to defend her positions."

O'Donnell's campaign said she returned to the state to attend church and keep a previously scheduled commitment to appear at a Republican picnic in Lincoln.