They could have another special election within a few months. Compared to the choice that Texas law and the courts are forcing on the 22nd district--a Democrat, a Libertarian, but no Republican who can or will serve--they would appreciate the chance to have a primary for a Republican nominee and then elect him in the general.
Lampson's toast in 2008 even if he does win this year.
Or they could just vote for the Libertarian. Better than Lampson.