There's a lot of confusion this morning about whether the shutdown deal includes an obscure provision that effectively ends the debt-ceiling forever.

Mitch McConnell's excellent idea. (Chip Somodevilla/Getty Images)

The culprit here is "the McConnell mechanism," a bizarre-but-useful idea Senate Minority Leader Mitch McConnell's office came up with in 2011. McConnell correctly recognized that the problem with raising the debt ceiling is that nobody wants to vote "yes" on it even though a majority of the Congress ultimately needs to vote "yes" on it. It is, in other words, a collective-action problem: Each individual legislator has an incentive to do something that's disastrous for the country as a whole.

McConnell's idea was to restructure the question so most legislators could vote "no" and the president would be the one to take all the blame. It's not the most profile-in-courage solution one could imagine, but given the circumstances, it's actually kind of genius.

The way it works is that the president gets the power to raise the debt ceiling and then Congress gets an opportunity to take a vote of "disapproval." If that vote passes Congress, then the president can veto the disapproval rule. If Congress can muster the two-thirds majority to overturn the veto, then the president's debt-ceiling increase is rejected.

In other words, the debt ceiling vote goes from a vote where a majority of Congress needs to vote in favor of it to a vote where up to two-thirds of Congress can vote against it.

We've been using the McConnell mechanism to raise the debt ceiling since 2011. If we made the McConnell mechanism permanent — something the Obama administration favors — it would basically disarm the debt ceiling forever. But last night's deal didn't make the McConnell mechanism permanent. It's only valid until Feb. 7, 2014.

Once it expires, we'll have to figure out how to raise the debt ceiling again. Odds are that whatever form that deal takes, it'll once again use the McConnell mechanism.