What is to stop a discharge petition this time?
Well, they usually take some time and effort to organize and it's not at all clear to me that, if it comes down to that, they'd be able to pull off a discharge petition before the session ends. You are right though that it's a definite possibility.
2. Karl Rove briefs the House GOP; plaudits from Bill Thomas; doubts from many others. The majority of the majority rule still stands. The bottom line: Bush needs to persuade about 40 House members to change their minds on a guest/temporary/amnesty/whatever program.