Robert Costa reported this morning that Republican leaders seem to have beaten back the truly stupid plan to deliberately seek a government shutdown over the Affordable Care Act. That brings us back to square one — which, alas, still makes a shutdown very possible.

Remember: In normal times of divided government within Congress, the House passes one version of what they want, the Senate passes an alternative featuring the other party’s priorities, and then the two get together and cut a deal. Oh, sure, they may battle up to the deadline to try to get the best deal, and along the way there are all sorts of bluffs as both sides try to get final numbers closer to their ideal points, but ultimately they’re basically going to find a solution that both sides can live with and both chambers can vote for.

The problem now is that, as Greg Sargent points out, it’s not really clear that Republican leaders can round up the necessary votes for normal spending bills even outside of Operation Obamacare Shutdown. The House hasn’t been having much success at passing normal appropriations bills, which are the foundation for any kind of continuing resolution they’ll have to pass this fall. They’re stuck between some members who are never satisfied with any level of spending cuts and others who object to those very unpopular cuts.

The numbers are important here: For normal to work, Republicans have to supply 218 votes for an opening bid (out of their current 233 members), and then probably come up with a majority of their conference for the final deal. This despite having a number of Republicans who are reluctant to ever vote for any government appropriations, and even more who are going to be terrified of voting for a deal endorsed by Barack Obama.

And remember who Republican leaders have to deal with here — people who believe (or at least say they believe) that they can plot openly to shut down the government over health-care reform for months and then expect that the public will blame Obama for that shutdown. Remember, too, that it’s possible that Costa was reporting GOP leadership spin and that Operation Obamacare Shutdown is still on (not to mention that there’s still the debt limit out there).

Which is only to say that even if congressional leaders and other sane Republicans do win on the Obamacare issue, a shutdown may happen anyway. Speaker Boehner has shown a remarkable ability to avoid apocalypses every time one of these deadlines comes up, and spin or no it’s clear he’s at least trying to avoid one this time. But congressional leaders have very limited ability to force the rank-and-file to cast responsible votes, and it’s always a struggle with this crowd (and with the various activists and fraudsters egging them on). There’s just no way of knowing whether one of these times, Boehner won’t be able to get over the finish line.