Why is he resigning?

DeLay's going to resign. You've heard it everywhere. But wait - resign? With the election just a few months away? Why not just not run for re-election?

Well, according to the Washington Post, "under Texas law he must either die, be convicted of a felony, or move out of his district to be removed from the November ballot." I can understand someone automatically being added to the ballot if they are the incumbent. But he can't request that his name be removed because he just doesn't want to run again? Now they have to hold a special election a couple of months before the regular election because he has to change his home address, thus "moving out of his district" in time to not be added to the November ballot, which would leave his seat open and in need of filling. It's all a waste of time and money. Who wrote this stupid law?