When it comes to cutting the national deficit, the plans proposed by Senate Majority Leader Harry Reid and House Speaker John Boehner are much more similar than they are different. It’s on the issue of raising the debt ceiling that the consensus cracks.

Both plans call for $1.2 trillion in reductions to discretionary spending. Both envision the formation of a bipartisan “supercommittee,” which would try to find consensus on a larger deficit-reduction package that, if it won a majority on the panel, would be immune to amendments and filibusters and be fast-tracked for an up-or-down vote in the House and the Senate.

Reid’s plan includes $100 billion in savings from “mandatory spending,” such as Fannie Mae and agricultural subsidies; $1 trillion in savings from winding down the wars in Iraq and Afghanistan; and $400 billion in reduced interest payments from cutting more than $200 billion in spending.

Boehner’s plan doesn’t specifically include any of that, but it’s fair to expect that his bipartisan committee would recommend many of the same mandatory savings, that the wars will end whether Boehner mentions them or not, and that if all that happened, his interest savings would be similar. So the plans’ immediate savings are nearly equivalent.

But that’s about as far as any agreement goes. Reid would use his $2.7 trillion in named savings to raise the debt ceiling through 2013. Boehner underplays his savings precisely so he doesn’t have to raise the limit through 2013. He doesn’t mention the war spending or interest savings, for instance, which Republicans counted in the budget put forth by Rep. Paul Ryan (Wis.) and which were part of Boehner’s negotiations with the White House. That allows Boehner to say he’s saving $1.2 trillion rather than $2.4 trillion, and thus gives him reason to raise the limit by only $1 trillion and demand that Congress go through another debt-ceiling debate next year. But that’s a choice he’s making, for reasons that will become clear in a moment.

Boehner’s plan would force a vote on a balanced-budget amendment to the Constitution by Oct. 1 and set strict limits on controlling spending in the future. If the limits were exceeded, the law would trigger automatic across-the-board spending cuts. And that’s all before 2012.

Once we get to 2012, either the new congressional committee would come up with a plan that Congress would approve or the debt ceiling wouldn’t be raised. That is to say, we either strike the sort of “grand bargain” that proved impossible this year ahead of the 2012 elections or go back to threatening the full faith and credit of the country — and we’d be doing it in the most politically polarized of all possible worlds.

The similarity of the two plans does suggest an obvious compromise. The final plan could include Reid’s initial spending cuts, which are slightly larger and more impressively stated than Boehner’s, and Reid’s longer debt-ceiling increase. But it also could adopt Boehner’s idea for across-the-board spending cuts — perhaps in an augmented form that includes penalties designed to bring Republicans to the table — if a second round of deficit reduction doesn’t pass. It could also include a vote on a balanced-budget amendment, although I dislike this policy and consider it a mistake.

That compromise would preserve the cuts that the two parties have agreed to, end uncertainty about whether Congress will violate the nation’s full faith and credit, and impose an enforcement mechanism that threatens a more severe form of deficit reduction — as opposed to an unnecessary economic crisis — if Congress can’t reach an agreement.

In theory, that should achieve almost all of Boehner’s goals. The only way it wouldn’t is if he actually wants to endanger the American economy ahead of an election year. But he wouldn’t want that, right?