The efforts by the White House to stop the Senate from passing legislation that would force Barack Obama to submit any deal with Iran for their approval have so far not borne much fruit. CNN reports this morning that the Foreign Relations Committee, chaired by the bill’s sponsor Senator Bob Corker (R-TN), will vote it onto the main Senate agenda as early as Tuesday. The Obama administration needs to find 34 Senate Democrats out of 46 who will stand with them in a veto override, arguing that the terms of the Corker-Menendez bill will scotch any deal with Iran:

The White House has engaged in an extensive lobbying campaign on the Hill and with constituent groups concerned about Iran ever since a framework agreement was announced on April 2. The U.S. and the other world powers negotiating with Tehran have until June 30 to hammer out the final details to seal a deal.

But so far, the administration hasn’t been able to win over all the Senate Democrats, many of whom believe strongly that Congress has a constitutional obligation to weigh in on a major nuclear agreement with a long-time enemy of the United States.

The bill already has nine Democratic co-sponsors and a handful of other Democrats have either expressed support or remain open to backing the bill. When combined with the Senate Republicans and one independent who support the legislation, that leaves backers just four shy of the 67 needed to sustain the veto that Obama has promised.

Just how dangerous is Corker-Menendez to the deal, though? At least one of the Senate Democrats that Obama has tried to woo thinks the danger is overstated, even though he supports the announced framework proposal in principle. Greg Sargent interviewed Sen. Tim Kaine (D-VA) yesterday about his support for Corker-Menendez, and Kaine argues that the bill “is deferential to the administration” while allowing the Senate to do its job. In his opinion, the bill has “zero chance” of harming negotiations (via The Hill):

PLUM LINE: Are you saying there’s no chance that a vote on Corker-Menendez before the deal is done could have the effect of derailing the process, by, say, empowering Iranian hard-liners to say, “See? Congress won’t allow the president to keep his end of the deal”?

KAINE: There is zero chance that Corker-Menendez passing will harm these negotiations. Iran is very sophisticated. They want out from under Congressional sanctions. They’ve known from the beginning that Congress would be involved in that. The question is, What is the process that Congress will use? The letter from the 47 Republicans is engagement under a free-for-all. It’s much better to have Congressional engagement under a standard that is agreed upon and timely, and I think this is deferential to the administration.

Bear in mind that Kaine has spoken approvingly of the deal in the past few days, so he’s not supporting Corker-Menendez as a way to torpedo the negotiations:

In fact, the way Kaine explains the bill, it may wind up backfiring on those who see it as a means to keep sanctions in place, practically speaking:

PLUM LINE: Part Two in the Corker-Menendez framework would be a vote to approve or disapprove the final deal. Can you explain what the various permutations are from that point?

KAINE: Let’s say Corker-Menendez passes. And let’s say there’s a final deal that looks like the framework. You’ll probably see in that 60-day review period discussions and expert testimony. You’d then likely see both resolutions of approval and disapproval of the final deal introduced.  The prospects of a resolution of approval passing both houses is tough. But a resolution of disapproval passing would be unlikely.

Either a resolution of approval or disapproval is subject to the 60-vote threshold. And if a resolution of disapproval passed, it would be vetoed by the president.  If he could convince one-third plus one in one house of Congress to stick with him on the veto, that amounts to “no action.” Which is then defined as “approval.” That’s a very deferential standard for the president.

PLUM LINE: So under the Corker framework, what Republicans will have accepted is this: If there aren’t 60 votes in the Senate for “disapproval,” or if there aren’t 67 to override it if there is a veto, the deal is essentially approved?

KAINE: The waiver of Congressional sanctions can begin. Yes. The high hurdle still remains the repeal of the sanctions statute. [This would make the lifting of sanctions, and the deal, permanent.] That would take an affirmative vote in both houses. But that would not likely happen for some time. Congress would want to wait, to test Iranian compliance.

In other words, Corker-Menendez would give the Senate some short-term leverage on the deal by removing Obama’s ability to waive statutory sanctions for a few months at a time, an authority that Congress authorized when it passed those sanctions into law. In exchange, it would set up an all-or-nothing vote on the final deal that essentially requires the Senate to re-legislate those statutory waivers at a 60-vote supermajority, and then have 67 votes for a veto override, if the deal looks bad. The default on this process would be the perpetuation of waivers on sanctions, at least through the end of Obama’s term — and probably for the foreseeable future, unless undeniable evidence of Iranian cheating arises. Once the deal is in place, there will be tremendous pressure on the next president to continue it if Iran is seen as compliant.

Why not just repeal Obama’s ability to waive sanctions entirely, and leave it at that? Corker may believe he can’t get to 67 votes with that approach, and he may be right. Kaine knows, though, that Obama can’t just keep waiving sanctions forever, especially given the short amount of time he has left in office. Congress isn’t about to repeal the sanctions while Obama is in office. Sargent makes a similar point on Twitter:

@ryanlcooper @Ali_Gharib @samknight1 Cong will vote on deal no matter what. Key Q is whether Corker locks them in to better process (1/2)

— Greg Sargent (@ThePlumLineGS) April 10, 2015

@ryanlcooper @Ali_Gharib @samknight1 Other key Q is whether hope of better process worth risk of early vote derailing deal (maybe not) 2/2

— Greg Sargent (@ThePlumLineGS) April 10, 2015

This may end up being a briar-patch bill in the end. The front-end danger for the White House is real enough, though, and having Kaine front this argument could be a huge problem for Obama and John Kerry. He’s not exactly Joe Manchin in the caucus, and his assessment that the bill is both necessary and better than any other alternative may carry enough weight to get it well past 67 votes, even if in the end Kaine will vote in support of the deal. It leaves the opponents of Corker-Menendez out on a limb, arguing in essence that their own chamber is irrelevant to the most important foreign policy decision of their term. With Kaine’s analysis, that may be a step too far for all but the most passionate supporters of the president in the upper chamber.