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 CoonsChris CoonsTrump, Democrats can bridge divide to make college more affordable Senate Dems urge Sessions to abstain from voting on Trump’s Cabinet picks Booker to vote against Tillerson MORE, the New Castle County executive, by double digits in the race for Vice President Joe BidenJoe BidenOvernight Tech: Meet the key players for Trump on tech | Patent chief staying on | Kerry aide goes to Snapchat | Uber's M settlement Biden's farewell message: Serving as VP has been my 'greatest honor' From credit cards to student loans, don't forget Obama's small victories MORE's old Senate seat.

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