NEW YORK (AP) – Old television appearances are coming back to haunt tea party-backed US Senate candidate Christine O'Donnell.

A few days after HBO's Bill Maher played a tape from 1999 in which the conservative Christian activist said that she dabbled in witchcraft while in high school, Fox News Channel's Bill O'Reilly said that he had tapes of "crazy stuff" that O'Donnell, the Republican candidate for Senate in Delaware, said during appearances on his programme.

O'Donnell rode the backing of the ultraconservative tea party movement to a surprise victory in Delaware's Senate primary last week. Her win over longtime Republican officeholder Michael Castle turned her from a political footnote into a national figure whose words drew interest outside of her tiny state.

O'Reilly did not play video on Monday night on 'The O'Reilly Factor', but both he and Maher have similar goals: booking O'Donnell on their shows now she's the political star of the moment.

Maher jokingly referred to his request as a hostage crisis, saying he'll show other clips from O'Donnell's 22 appearances on 'Politically Incorrect' during the 1990s unless she agrees to come on his current show, 'Real Time with Bill Maher'.

Maher said he'd prefer a new appearance to old clips.

"Christine and I have always had, I thought, a good, adversarial relationship and I just thought (an appearance) would be good for her and good for us," Maher said. "I wouldn't be mean to her. You can't be mean to her."

Even though they disagree politically, Maher said that "I like her a lot" – hence her repeated appearances on 'Politically Incorrect'.

He said he believed O'Donnell could be more successful as a politician than Sarah Palin. O'Donnell's "ideas are just as loony, but she's not nasty," he said. "She's nice. She's got that Reagan thing going for her."

O'Donnell cancelled scheduled appearances on Sunday morning TV news talk shows after Maher aired the old clip on Friday. Her spokeswoman said an appearance on Maher's show is unlikely for the same reason she backed out of the other shows, because of a need to stick to Delaware.

"The focus is not on that," said the spokeswoman, Hayley McConnell. "The focus is on talking to Delaware residents and pushing ahead with the campaign to get a win in November."

O'Donnell should be wary of Maher even if he professes fondness for her, said Brent Baker, a vice president for the conservative media watchdog Media Research Center. He said it's not "good manners" to go back and select old clips to embarrass the candidate.

"She loses either way," he said. "But at this point, it's coercion: 'come on my show or else I will screw you over'. That's kind of caving into blackmail there."

O'Reilly made no overt threats, saying on his Fox show on Monday night that he was trying to be fair to O'Donnell.

"She's been on this programme a number of times, and we have some kind of crazy stuff that she said," he said. "We're not going to play it yet. I don't think it's relevant yet. We'd still like Ms O'Donnell to come on 'The Factor'. I'm not in the business to injure her."

O'Reilly said on his show that "the more they do this to O'Donnell, the stronger she's going to get." Maher said he wouldn't reveal what O'Donnell talked about in other 'Politically Incorrect' appearances, but he said he didn't believe her 1999 comments about witchcraft were particularly damaging. "If I really thought I was hurting her, I wouldn't do it," he said. "I don't think she should be in Congress, but I don't think there is anything on the tapes that is going to hurt her."

It's not clear who actually owns the tapes to his old programmes, but Maher said he had them. He doubts others have access to them; they would have had to record the shows, keep those tapes for years and transfer them for use digitally. "I'm pretty much the keeper of the flame," he said. "It's lucky I'm a hoarder."