I can't tell you how many times I've had conversations with politicians who've done something morally reprehensible but not indictable, yet still think they should be able to stay in office. The office isn't a right. It's a kind of loan.
Take Hispanic voters. They favor Democrats because they like the party's programs, from health care reform to government spending on education. It's not because the Republicans don't have a big enough Office of Hispanic Outreach.