Well, when something weird is going on with a Republican politician, the automatic Google search is:
[politician's name] gay
How big a role do you think blackmail plays in politics these days? If you had a list of all the gay Republicans, plus incriminating photos of them, how much power could you wield in Washington?
In the comments, Tommy points to a story saying:
"So, aides said, the senator decided to leave by year’s end to circumvent new lobbying rules — instituted by Congress this year and effective in 2008 — that that would bar members from lobbying their colleagues after two years. The so-called “revolving door” policy in effect now keeps former members from lobbying their colleagues for one year. The changes were made in the wake of the scandal surrounding former lobbyist Jack Abramoff."
So, perhaps Lott isn't resigning over being with a male whore. Instead, he wants to be a male whore (lobbyist division).