U.S. Homeland Security Nominee Withdraws

This seems to be an American phenomenon - politicians, even (especially?) ones that has been around for a while, having to take themselves out of public office once word gets out that the help is either of dubious immigration status or hasn't had taxes or social security paid for them properly (see further down the CNN article for a list of recent examples). It certainly doesn't happen in Canada as far as I know.

I wonder, however, if this is simply the American version of the old Canadian standby of a politician removing himself from scandal by copping to a relatively minor transgression, usually involving meddling in a judicial matter for a constituent. These things usually come to light well into their political careers; it's curious that they either haven't been identified before or that the politician wouldn't know better. Might something embarrassing from Kerik's past have come out during confirmation hearings? I'd have thought that the administration would have done it's due diligence before an announcement was made.

But then again, maybe I'm just being cynical.