After getting 42 votes in support of Barack Obama’s deal with Iran on nuclear weapons, Harry Reid led two successful filibusters of the disapproval bill that would have gone down to a veto anyway. The House easily passed its version of the disapproval bill, with a handful of Democratic votes to provide a wide — but not veto-proof — bipartisan margin. Stymied twice on getting an up-or-down vote for the bill before the 60-day window expires (at least by the White House’s calculation), Mitch McConnell plans to force Democrats into a potentially embarrassing vote on Thursday in an attempt to end the filibuster:

Senate Majority Leader Mitch McConnell (R-Ky.) plans to force Democrats to walk the line on the Iran nuclear agreement, teeing up a vote on a contentious amendment on the deal.

The Republican leader scheduled a procedural vote on an amendment that would block President Obama from lifting sanctions against Iran under the nuclear deal until Iran publicly supports Israel and releases Americans currently held in Iranian prisons.

Under Senate rules, the vote would occur Thursday, which is also the deadline for Congress to pass legislation on the Iran nuclear agreement.

A condition of publicly supporting Israel is so obvious a deal-killer that it may let Democrats off the hook. However, a condition of blocking any sanctions relief until Iran releases four American prisoners is not only defensible, it points out the indefensible neglect of those detainees by the Obama administration. A competent negotiating team handing the Iranians basically everything they wanted would have gotten that much in return. Not only should that condition not be a deal-killer, it should have been a condition for even discussing sanctions relief.

Reid has Senate Democrats marching in lockstep with the White House on a deal that’s already widely unpopular. Only 21% of Americans support it, according to the last Pew Research poll, and that’s not even taking into account the hostage situation. McConnell’s amendment will force Democrats to explicitly attach themselves to Obama’s decision to leave American hostages to rot in Iran, and that will make a bad situation worse for them with voters in 2016.

Let’s say that Democrats double down on this and filibuster the amendment. What’s next? House Republicans want McConnell to follow Reid’s example and nuke the filibuster for good:

Multiple House Republicans want Senate leaders to “go nuclear” over the Obama administration’s deal with Iran now that Democrats have stymied efforts to derail the accord by conventional means.

A small but growing number of GOP lawmakers say that Senate Majority Leader Mitch McConnell (R-Ky.) should invoke the “nuclear option” to change Senate rules and prevent a filibuster on a resolution to kill the deal. …

“This was something with the Iran deal, the fact that it didn’t get debated, it didn’t get voted on — there’s a lot of people that are very, very upset about this,” said Rep. Vern Buchanan (R-Fla.) in an interview on Tuesday, a day after he sent a letter asking McConnell to change the Senate’s rules.

Buchanan said that he wants to see the upper chamber eliminate the filibuster entirely, though others are calling for a more modest step to get rid of the procedural holdup only in specific cases, such as with the Iran deal.

Rep. Steven Palazzo (R-Miss.) wrote a letter to McConnell last week calling for a change in rules for the Iran bill. Rep. Lamar Smith (R-
Texas) — chairman of the House Science, Space, and Technology Committee — is currently circulating a letter among fellow lawmakers with a similar call.

“Some pieces of legislation, like the Iran nuclear deal, are simply so consequential that they demand revisions to the Senate’s procedures,” Smith wrote in the draft letter.

Reid pulled this stunt in the last session to get Obama’s judicial picks out of the Senate. Holding an up-or-down vote on a foreign agreement of this consequence rises above that issue by leaps and bounds. McConnell, having served in the minority long enough, understandably wants to keep that firewall, but Reid already set that precedent. The next time around, either he or another Democrat will demolish it to get what they want, and it won’t be on anything as critical to global security as this.

If it comes to that, though, it may be that Democrats will cave and allow the up-or-down vote on the deal rather than lose that leverage. Quite frankly, filibustering the deal vote is an inexplicable strategy anyway. It puts Senate Democrats at risk for no reward, only tying them to a wildly unpopular deal even more tightly. Obama already owns this deal, so the filibuster isn’t protecting him from a politically risky veto; the political risk has already been assumed by Obama. Even some who support the deal have argued that blocking the Senate from an up-or-down vote makes it look even more illegitimate, especially since Democrats can sustain a veto in both chambers of Congress. Does Reid really want to throw away his filibuster ahead of some very contentious votes on what’s already a sure thing?