I think she’s right, and as you say, it was true in the case of Obama, too. But much depends on the will of the press to make an issue of things, and in the case of Obama, they covered for him.
That said, one thing that Obama had a lot of experience at was politics. Not governing, not legislating, simply politics and running for office. So he knew how to ride things out, how to deflect things, and probabably also how to silence the opposition (he learned the game in Chicago, after all).
Cain has no political experience, except one failed run for office, and that is the thing that is showing. He had three weeks to do something about this, or at least to get his story straight, and he didn’t. To me, that says he probably reads FR and believes he can do no wrong. To believe his own publicity is a dangerous thing for any candidate, and if Cain wants to remain in the race, he’s got to be more objective and professionalize a bit. Maybe he needs to hire new managers or something.
Yeah, perhaps Cain’s inexperience in dealing with these situations is what will kill him off. IMO, he should have deflected it...something like “why yes I have heard that might be the case for something from twenty years ago but I was more involved with applying for a schlarship as a foreign national while giving the public the impression I was a US citizen at that time.” Use humor to put the spot light on his enemy or perhaps something like “I don’t recall the issues involved because I was trying to stop the imposition of mandatory public health care on restaurants in Massachusettes.”
Cain is doing such a poor job he needs to hire you as his savior and campaign manager.
In the meantime he'll just have to plod along without you, topping all polls along the way.