David Hill's makes a good point:

So why do “perverted” politicians keep on running when their lies are almost always eventually exposed? Do they enjoy living on the edge until their outing? Many obviously think that what they do after hours is their own private business. Well, here is some news. It’s not private business, especially if you are running with the imprimatur of the Republican nomination. And if you are living a lie, you are killing your party. Look at what’s happened in Florida. Republicans are forced to throw hapless Joe Negron into the fray as a last minute replacement for Foley. With only a month left, what’s the poor guy to do?

As mentioned, I don't believe that Speaker of the House Dennis Hastert ought to be tossed from leadership. The original emails were considerably tamer than what has come out since. Foley could plausibly claim that he didn't mean to be too forward and lied and claimed that there wasn't much else out there that would hurt him. Hastert understandably wanted to believe Foley and there were things seemingly of more immediate importance. In retrospect it wasn't the right call to make, and maybe it should have been apparent at the time, but hindsight is 20/20.

The biggest failure here is a lack of information. Had Hastert known what has since been revealed, obviously he would have done more. The problem, which the Hill column deals with, is that candidates and officeholders are seemingly expected to police themselves. That's the problem.

The solution, it seems to me, is that each party ought to have a group of investigators whose only job it is to follow up on these things. That way, when the suspicions were aired, they would have had a place to go and be investigated without an official complaint being lodged. From what I understand at least some candidates have people investigating the employer to find out what can be found out, but it would be much better if done on the party level. Senator Smith may be willing to take a risk that someone won't be discovered when he runs for president, but that doesn't mean that the party should be willing to take that risk, too.