The White House’s drive to steamroller the Iran deal through Congress in the face of opposition from a bipartisan majority has finally borne fruit—Sen. Barbara Mikulski (D-Md.) today announced her backing for the deal, handing President Barack Obama the 34 senators he needs in the event that he has to veto any vote of disapproval.

Mikulski’s statement may not, however, be enough to satisfy the administration. Talk of a filibuster to prevent a vote is growing louder. To achieve that outcome, the White House requires seven of the ten remaining senators who are currently undecided to declare themselves in favor of the deal.

This raises the pertinent question of whether the undecideds would—assuming they decide to support the nuclear deal with Tehran—also favor a filibuster as a procedural means of obtaining legislative sign-off. The filibuster route denies both opponents and supporters of the deal the opportunity to go on the congressional record with their positions, as opposed to simply trading arguments and barbs in the media. It will also mean that critical reservations about the deal, even among its supporters, will not be articulated in Congress—which is precisely what the administration wants. As deal supporter Sen. Chris Murphy (D-Conn.) told Politico, “There’s a cost to the international credibility of the country and this president if a motion of disapproval passes the House and the Senate.”

That view isn’t universally shared. As Sen. Chris Coons (D-Del.), who yesterday came out in favor of the deal after weeks of deliberation, told CNN: “I think it would be really regrettable if we didn’t ultimately go to the floor and cast our votes for or against this deal.” Meanwhile, remarks made by some of the senators who are still wavering suggest that they, too, would opt for a vote rather than a filibuster even if they did decide to support the deal.

For example, Sen. Richard Blumenthal (D-Conn.), who is under tremendous pressure from the White House to back the deal, has insisted that he will make his decision based on the deal itself, while ignoring the political horse-trading that has accompanied it. Blumenthal told National Journal in July that he “probably” would be unable to support the deal because it involved lifting United Nations and European arms embargoes on Iran. Speaking to The Hill Tuesday, Blumenthal said that there are “a number of downsides” to the nuclear deal, including the billions of dollars that will flow to Iran through sanctions relief—funds that can easily be injected into Iran’s terrorist proxies throughout the region. He also expressed discomfort with the inspections regime envisioned in the Joint Comprehensive Plan of Action (JCPOA), the deal’s formal title, as well as “the potential for nuclear weaponization at the end of 10 or 15 years.”

Would Blumenthal be content for these vital points, which reflect the general skepticism towards the deal among American voters, to be buried by a filibuster?

Much the same question can be posed to Sen. Cory Booker (D-N.J.), whose close ties to both the Jewish community and the Obama administration are well known. While Mikulski’s decision has spared Booker from a major conflict with Obama, should he oppose the deal, he is surely aware that he will be the recipient of angry criticism if he ends up supporting the deal without demanding a Congressional vote at the same time.

The same is true for the other waverers like Sen. Joe Manchin (D-W.Va.) and Sen. Ben Cardin (D-Md.). Manchin has indicated that he will cautiously support the deal, having declared at the end of August, “We don’t trust them [the Iranians] and they don’t trust us…I would be in support of this agreement if it allows us to reboot and retrigger the sanctions if—and people say it’s only a matter of time—and when they violate the conditions of the agreement.” In the light of these publicly expressed reservations, it is legitimate to ask whether Manchin would be prepared to sacrifice an honest, on-the-record debate in order for the president to push the deal through.

Cardin, for his part, has said that he is “not satisfied” with the details surrounding the International Atomic Energy Agency’s agreement with Iran on investigating previous nuclear activities at Iran’s Parchin facility. A congressional debate on the deal would certainly push the IAEA’s side agreements with Iran into the spotlight; these have not been disclosed to Congress despite the fact that the Iran Nuclear Agreement Review Act specifies that “side agreements” must be provided in the review materials.

Following Mikulski’s announcement clinching the vote for the White House, the undecided senators must now consider whether they will play ball with the administration over a filibuster whose purpose is to mask the very real doubts about the nuclear deal even among the president’s allies.

[Photo: NASA / flickr]