(Updated 4:40 p.m. ET with O'Donnell campaign response)
(CNN) - Meghan McCain is known for speaking her mind, and her views on Delaware Republican Senate candidate Christine O'Donnell proved no exception Sunday.
"I just know, in my group of friends, it turns people off because she's seen as a nut job," McCain said on ABC's "This Week" program. "It scares me for a lot of reasons."
The daughter of Arizona Republican Sen. John McCain said O'Donnell's candidacy sends a message to the younger generation that you can just "wake up and run for Senate," regardless of past experience.
O'Donnell, an unsuccessful Senate candidate in 2006 and 2008, has received national attention this time for her Tea Party backed victory in the Republican primary over nine-time U.S. Rep. Mike Castle, a former governor.
In recent weeks, decade-old video footage surfaced showing O'Donnell challenging the theory of evolution and talking about having "dabbled in witchcraft."
"Christine O'Donnell is making a mockery of running for public office," McCain said. "She has no real history, no real success in any kind of business."
The program included some comments from O'Donnell from an interview broadcast last week, prior to McCain's criticism Sunday.
O'Donnell's campaign later responded to McCain.
"Christine overwhelmingly won her primary battle against the establishment candidate, so Ms. McCain's vast experience in politics and running for office probably won't influence many Delawareans of any age to listen to her latest rant," Matt Moran, O'Donnell's campaign manager said in a statement.
O'Donnell has depicted her candidacy as an effort to give ordinary Americans upset with the direction of the country a voice in Washington.