Every Republican candidate is going to be smeared by the media. That's given, and there is no use to complain about it no matter how unfair and unjust it is. So, whether they can stand or not depends on whether they have prepared for the worst or not. And more importantly, whether they have something that might be used or not. Cain obviously made a huge mistake when he didn't think that his relationship with the last accuser wouldn't be an issue. I don't know if it's an affair, but he made it worse by hiding it from his wife.
So, I disagree that vetting doesn't matter. It does.