Republican presidential frontrunner Herman Cain's shifting response to allegations that he sexually harassed two women in the 1990s has turned a damaging news article into a full-blown campaign crisis. On Sunday night, Politico reported that when Cain was CEO of the National Restaurant Association (NRA), two female employees accused him of making unwanted sexual advances, and both left the lobbying group with "separation packages that were in the five-figure range." After a day of media digging and several press appearances by Cain, what do we know about the allegations, and what questions remain? Here's what you need to know:

What do we know about the women?
Politico says that it knows both of their names, but won't divulge them. NBC News independently confirmed the case of one woman, and won't disclose her name either. The National Restaurant Association says it won't give up any details on its former employees or any legal settlements. On Monday, Cain told Fox News' Greta Van Susteren that one of his accusers was a writer in the NRA's communications department who was in her late 30s or 40s. The other, Cain says, worked for the NRA's political action committee. Both women have reportedly signed non-disclosure agreements.

What details do we know about the alleged harassment?
The Politico story revealed very little — and said only that the allegations included "innuendo or personal questions of a sexually suggestive nature," an invitation to one of the women to come up to Cain's hotel suite during a work conference, and "physical gestures that were not overtly sexual but that made women who experienced or witnessed them uncomfortable." The gesture was probably from an incident in his office with the writer, Cain told Van Susteren. "I made a gesture saying — and I was standing close to her — and I made a gesture saying you are the same height as my wife. And I brought my hand up to my chin saying, 'My wife comes up to my chin.'"

Does Cain deny the allegations?
He denies ever sexually harassing anyone, although he told PBS's Judy Woodruff that inappropriate behavior could be "in the eye of the person that thinks that maybe I crossed the line." Still, he calls the allegations against him "totally baseless."

But what about the settlement?
That's a bigger political problem for Cain, particularly because his account of the settlement has shifted. "I am unaware of any settlement," Cain said at the National Press Club on Monday. "I hope it wasn't for much, because I didn't do anything." But by the time he talked to Van Susteren later that day, Cain not only remembered the settlement, but also several details: The women "were demanding a huge financial settlement," but "we ended up settling for what would have been a termination settlement" of "maybe three months' salary. I don't remember. It might have been two months. I do remember my general counsel saying we didn't pay all of the money they demanded."

Are his denials credible?
Several NRA board members quoted by Politico say they didn't know about any sexual harassment claims against Cain, and that such behavior would have been out of character. But Cain's unravelling story "is fast becoming a mess," says Jennifer Rubin in The Washington Post. "The never-ending stories here suggest Cain hasn't been honest with the public," and "that's going to be harder to explain than the original allegations." Regarding those harassment allegations, Rubin adds, "nuisance claims are made and settled every day. But a substantial amount of money doesn't usually change hands unless, from the employer's standpoint, there are 'bad facts.' It would provide some indication of how bad the facts were if we knew if the five-figure settlement was closer to $10,000 or to $99,999."

Are any other harassment stories likely to come out?
No, Cain told Fox News on Monday. And if any do, "I assure you people will simply make them up." But Cain's inconsistency in telling his side of the story is "leaving some to wonder if another shoe in the burgeoning sexual harassment scandal is going to drop," says James Oliphant in the Los Angeles Times. Stay tuned.

Sources: Fox News, Los Angeles Times, New York Times, NBC News, Politico (2), Talking Points Memo, Washington Post (2), Washington Examiner