National Review (11/29/11):
In a conference call this morning, Herman Cain told his senior staff that he is “reassessing” whether to remain in the race. He will make his final decision “over the next several days.
[...]
Now, with this latest one, we have to do an assessment as to whether or not this is going to create too much of a cloud, in some people’s minds, as to whether or not they would be able to support us going forth,” Cain said.
So the previous allegations of sexual harassment left him unphased, but new allegations of a supposedly consensual affair are an immediate cause for dropping out of the race?