Boehner has long agreed to apply the Hastert Rule to the House bill, but had remained mum on any conference bill (the group of House and Senate members who get together to hash out a final bill). There was a growing fear from conservatives that Boehner would back some conservative version, but would then betray them when the conference bill came back allowing a free vote. This morning he clarified that even the conference bill would be subject to the Hastert Rule.
Thus, the prospects are suddenly dimmer ... assuming Boehner isn't lying to his caucus. Or maybe he thinks he's telling the truth, but could change his mind later on as people ask him to choose between the death of his speakership, or the death of his party. It would suck to be labeled "the guy who killed the GOP", particularly if the establishment lines up a cushy million-dollar K-Street golden parachute for him.
That's why conservatives will fight to prevent anything from happening. No bill means no conference report means no chance for Boehner to ratfuck them.
Ultimately, it'll come down to whether enough Republicans want to stay in the electoral ballgame, or whether they're content to relegate themselves to permanent minority status.