Herman Cain’s burgeoning scandal isn’t going away any time soon, after the candidate stepped on his own message late Monday.

While Cain showed some ability to control his message during the course of day, by the end, he was in full backpedal mode. After previously saying he didn’t know about any settlements reached with women who had accused him of sexual harassment, Cain detailed a settlement in an interview with Fox’s Greta van Susteren taped for tonight. And in an interview with PBS, Cain said he couldn’t recall whether he had invited one of the women up to his hotel room.

It was a whirlwind day that suggests the amateur political candidate still has his work cut out for him as he deals with a growing scandal.

On Sunday night, Politico published a story reporting that Cain, while president of the National Restaurant Association in the 1990s, was accused of sexually harassing two women. Though the women remained anonymous in the story, the Web site reported that they left the association with financial settlements.

Despite stumbling early to beat back the story – including an awkward exchange in which Politico’s Jonathan Martin confronted Cain and was then asked himself whether he had ever been accused of sexual harassment – Cain’s team responded with far more vigor than to past dilemmas and was on-message most of the time.

Chief of Staff Mark Block got the ball rolling with an appearance on MSNBC’s Daily Rundown with Chuck Todd this morning, laying out the campaign’s case that Cain had never sexually harassed anybody and that it was not aware of any cash settlements that were paid out.

An appearance later on Fox News was pivotal, as Cain himself appeared for the first time and tackled questions about the incident. He said that he had been “falsely accused” of sexual harassment.

By the time he got to the National Press Club early this afternoon, Cain seemed more than comfortable and was clearly on offense. He accused his critics of a “witch hunt” and denied any knowledge of settlements reached with the women.

“I was falsely accused of sexual harassment, and when the charges were brought, as the leader of the organization, I recused myself and allowed my general counsel and my human resource officer to deal with the situation, and it was concluded after a thorough investigation that it had no basis,” Cain said.

What we had seen to that point was consistent message management from Cain and his campaign.

“It doesn’t get any stronger than a direct, on-the-record, on-camera, denial,” former White House press secretary Ari Fleischer said. “Absent the women stepping forward themselves to make a credible counter claim, Cain’s denial is what we have to go on, unless you’re more inclined to believe anonymous sources.”

The problem for Cain is that, after a decent early response, he stepped on it when he detailed a settlement with one of the women. Conservative columnist Byron York reports that Cain told van Susteren that “we ended up settling for what would have been a termination settlement.” Then, in an interview with PBS’s Judy Woodruff, he said he couldn’t recall whether he had asked one of the women to his hotel room.

Given Cain had previously denied knowledge of any settlement and of what the allegations were about, some will read this as him changing his story. And that’s not good for his long-term prognosis.

“The key thing to watch for is whether his story changes,” said renowned crisis communications consultant Eric Dezenhall. “The more a story changes, the more it signifies that there may be something deeper.”

Cain will continue to have to deal with the questions during his D.C. media blitz .

But unless more evidence emerges, the old political truism (recently re-hashed in the Marco Rubio situation) will probably apply here as well: critics will criticize, while people who are inclined to believe Cain will continue to do so.

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