Delaware GOP Senate nominee Christine O'Donnell said Thursday she regrets making a campaign ad that addressed her past involvement with witchcraft, saying it backfired. 

O'Donnell, a conservative activist who pulled a stunning upset of nine-term centrist Rep. Mike Castle in the state's Senate GOP primary, said that her intention was to "kill" the chatter among the political class about her past controversial statements.

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"Yeah, yeah — you know I haven't publicly stated this and I don't know if I will get in trouble for saying that, but our intention was to kill it. And that's not what happened," she said on ABC's "Good Morning America."

Democrats have pounced on O'Donnell's past statements about sexuality and masturbation to paint her as an extreme candidate who is out of touch with Delaware voters. 

During an appearance on Bill Maher's "Politically Incorrect" in the 1990s, O'Donnell said that she had "dabbled" in witchcraft at a younger age.

O'Donnell's ad released early this month sought to break down those perceptions. "I'm not a witch, I'm nothing you've heard. I'm you," she says in the 30-second spot.  

But the ad continued talk of her past and was lampooned by "Saturday Night Live."

The Republican nominee trails Democrat Chris CoonsChristopher (Chris) Andrew CoonsSenate ethics panel wants details on sexual harassment allegations American innovation depends on strengthening patents Tax reform and innovation – good news and a cloud MORE, the New Castle County executive, by double digits in the race for Vice President Joe BidenJoseph (Joe) Robinette BidenOvernight Tech: FCC won't delay net neutrality vote | Google pulls YouTube from Amazon devices | Biden scolds social media firms over transparency Medicaid funds shouldn't be used to subsidize state taxes on health care Biden hits social media firms over lack of transparency MORE's old Senate seat.

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