Opinion writer

Earlier today, Senator Michael Bennet of Colorado came out for the Iran deal, a big get for supporters. Only a few minutes later, however, Senator Ben Cardin of Maryland came out against it. That’s important, because he’s the ranking Dem on the Foreign Relations Committee — if he had backed the agreement, the five remaining undecided Dems would have had more cover to back the accord.

Right now, the key question is whether supporters will get 41 votes to filibuster a resolution disapproving of the deal — enough to block that disapproval resolution and avoid the need for a presidential veto of it and a subsequent veto-override fight. The deal is going forward no matter what, since a presidential veto will be sustained, but supporters would like to avoid a veto battle.

Whether supporters do or don’t succeed at that has come down to some intense and hard-nosed overlapping procedural and political deliberations that are more complicated and intrigue-laden than you might think.

As of now, 38 Democrats support the deal. There are five remaining undecided Democrats: Joe Manchin, Richard Blumenthal, Maria Cantwell, Gary Peters, and Ron Wyden. Manchin, however, is on record saying that he will not support a filibuster of the disapproval resolution, even if he does ultimately vote against that resolution in the final vote. Supporters have not given up on changing his mind, but if he does oppose the filibuster, then supporters need to get three of the remaining other four undecided Dems to support the filibuster to get to 41.

But here another complication arises. Two Senators who support the deal — Chris Coons and Heidi Heitkamp — have not said whether they will support the filibuster (though they can be counted on to support the deal in the final vote). If they don’t filibuster, then supporters can’t get 41. Thus, the question of whether a veto-override fight can be avoided turns heavily on whether there is a small block of Dems who support the deal but decline to filibuster the disapproval resolution.

Republicans have been darkly warning Democrats not to filibuster — never mind how often they did so in the minority — arguing that they will be flouting the will of the American people if they do. Dems have pushed back on this charge in substantive terms. Ben Marter, a spokesman for Dick Durbin, has charged Republicans with “faux outrage,” noting that they voted for the Corker framework that enabled the disapproval resolution to be blocked with 41 votes.

But there’s a cruder political calculus that is underlying final deliberations. Some Democrats who support the deal may decide not to support the filibuster, to avoid what they think might be politically damaging GOP attacks on them if they do support the filibuster.

But Democratic leaders are warning these remaining undecided Dems that this is a trap. The argument being made to them is that if they don’t support the filibuster, they will actually have to take more votes on the deal — exposing them more politically — than if they do filibuster. Here are the two possible courses of action for them:

A) If those Dems don’t support the filibuster of the disapproval resolution, then they have to take at least three votes:

1) A vote against the filibuster of the disapproval resolution (in which case the filibuster would get broken).

2) A vote for the deal, in the form of a vote against the disapproval resolution in the final vote (in which case the disapproval resolution would pass, since it only needs a simple majority, and Republicans have that).

3) Another vote for the deal in the form of a vote to override Obama’s veto of the disapproval resolution.

OR

B) If those Dems do support the filibuster of the disapproval resolution, then they have to take only one vote:

1) A vote for the deal in the form of a vote to filibuster the disapproval resolution, which, if it held, would end this whole affair and the deal would go forward.

In Scenario B, there would be one vote — a vote to allow the deal to go forward. In Scenario A, there would be three votes, two of which would be votes to move the deal forward, including a vote to sustain a presidential veto in the face of a majority of Congress opposing the deal. It’s hard to imagine that Democrats somehow get attacked less over their support for the Iran deal in Scenario A. In this scenario, arguably the attacks on Dems could be more potent. (And anyway, opponents of the deal want a messy veto override fight because they think it’ll undermine confidence in the agreement.)

Any Democrats who think they can easily explain their way out of that multi-vote procedural morass (“I backed the deal, but I didn’t vote to filibuster!!!“) should look back at the ads that ran against John “I voted for it before I voted against it” Kerry.

**************************************************************

UPDATE: My math was a bit off; I’ve fixed it. Doesn’t change the larger point.