Well, two things, actually: Control of the House in the next session, and the 2014 GOP primaries.
I'm reminded of parenting teenagers (and I had four at the same time -- I speak from experience here). When the argument reaches the stage where the protagonist is incoherent, it usually means there's a different and far more basic objection. That's where we are here, in GOP incoherency. Why? Well, for starters, all those GOP House members we assume will vote for a clean CR have the sword of Damocles hanging over their necks, in the form of a primary challenge from the right. When the Chamber of Commerce announce they'd consider funding GOP moderates in the next election cycle, that took off some of the edge; but if the Koch-fueled orgs match or exceed with their own fire-breathers, at a minimum the last of the GOP moderates face exceedingly expensive primaries in 2014. We all assume Boehner is bluffing to keep his job; it's just as likely some of those GOP members the MSM has whipped in support of a clean CR are doing the exact same thing. Sure, it might not make a difference -- they might face a well-funded Democratic opponent -- but at least they'll have money for the fall campaign. Boehner may be stalling a vote in part to help those members; after all, he'd rather have them in a majority than yet more Tea Partiers.
That brings me to my second point. Boehner is perilously close to losing the House majority. In fact, he probably loses it if he allows votes on a clean CR and a clean debt ceiling raise. If the CR passes, it virtually guarantees hard-right challenges; if it fails, it likely results in better chances for Democratic challengers. Either way, Boehner loses.
In a sentence, then: Boehner's only hope of keeping a GOP majority in the House come 2015 is to prevent clean votes on the CR and the debt ceiling. The ball's in our court to force the issue. I've been saying for a while that I didn't see a way to take the House; now I do, but it depends on forcing Boehner's hand.