Senator Bob Corker (R-TN) speaks with reporters after a meeting with US Secretary of State John Kerry and other Senators on Capitol Hill April 14, 2015 in Washington, DC. (BRENDAN SMIALOWSKI/AFP/Getty Images)

Sen. Bob Corker (R-Tenn.) and Senator Ben Cardin (D-Md.), the leaders on the Foreign Relations Committee, have announced a compromise recasting the Corker-Menendez bill to deal with objections from Senate Democrats. The compromise is an improvement, but it still poses a risk to a final deal with Iran.

The Huffington Post outlines the new Corker-Menendez bill’s key provisions. Here’s the gist:

1) Obama still must submit the final deal to Congress, but the period during which Obama is restricted from lifting sanctions to implement the deal has been cut in half, from 60 days to 30 days. During that period, Congress may vote to approve or disapprove of the final deal. After that, the president has 12 days to veto the bill; and if he does; Congress has another 10 days to override that veto.

That’s an improvement. It means Congress can’t delay implementation of a deal for as long as before.

2) Under the new framework, the president would certify to Congress every 90 days that Iran is complying with the final deal, but he would no longer have to certify that Iran had not directly supported a terrorist attack targeting an American or American business.

That’s also an improvement. Critics had feared this would introduce another condition that could scuttle a final deal after it is reached and being implemented, even though it is unrelated to Iran’s nuclear program. This also could have caused Iran to walk before a deal was reached.

3) The new framework still preserves the ultimate approve/disapprove Congressional vote on the deal itself, i.e., the vote on whether the president has the authority to temporarily lift sanctions to implement a final deal. (The permanent lifting of sanctions would also require a Congressional vote later, but Congress would probably want to wait on that vote, anyway, to see if Iran is complying.)

The big question is whether this last provision will derail the process before a final deal can be reached.

First, let’s understand what the risk really is here. The problem isn’t necessarily that Congress could end up voting down a deal later. It’s perfectly possible that many Democrats who support Corker-Menendez could ultimately support a final deal. Indeed, that might be easier for them to do after they’ve proved their “toughness” by backing Corker-Menendez. Under this framework, if Congress disapproves of the final deal, restricting Obama’s authority to lift sanctions, and Obama vetoes that, but Congress fails to override that veto, the deal goes forward in the short term anyway. That’s because under this framework, not passing a restriction of Obama’s authority to lift the sanctions is the equivalent of approving that authority. It’s very hard to imagine Democrats — even ones who support Corker-Menendez — helping to override a veto and killing a final deal after it has been reached.

So Corker-Menendez could very well become law, and Congress could still subsequently fail to scuttle a final deal (if it is reached).

Rather, the danger is that a vote now on Corker-Menendez could scuttle the process before a deal is finalized, by sowing fears that Congress ultimately will not allow the president to keep up his end of the bargain. Senator Tim Kaine, a leading supporter of Corker-Menendez who by all appearances really wants a final deal to work, assures us that this isn’t going to happen. He says Iran understands the process here and gets the endgame laid out in the above paragraphs. However, no Corker-Menendez backer has convincingly explained why this vote has to happen now. All of this could almost certainly be structured so Congress could hold its initial vote to create the Corker-Menendez framework on the day the deal is signed, and the outcome from there on out would be procedurally identical.

So the question is, Why risk scuttling the whole process with a vote before a deal is signed, when all the same procedural benefits of Corker-Menendez — including Congressional oversight of the process — could be obtained with a vote later? I still haven’t heard a good answer to that.

But that question may be moot; it looks as if the die is now cast. Today the White House confirmed that the president will probably sign the new version of Corker-Menendez, provided it doesn’t get worsened by the amendment process, in which Republicans may try to insert additional provisions toughening the conditions on a final deal.

My strong suspicion is that the White House accepted the new framework because it has no choice. Democrats had already predicted that the new Corker-Menendez framework would secure a veto-proof majority. Whether that’s true or not, Congress is going to vote on a final deal one way or the other, so the White House is probably accepting this framework as its best bet. The White House may even try to put a positive gloss on this outcome, claiming it doesn’t threaten the chances of a final deal anymore, or at least that this is an unnecessary complication, but not much more than that.

But outside critics and/or some Democrats will likely continue to point out that there remains a substantial risk even the new Corker-Menendez bill could derail a final deal before it is signed. Those who hope for a deal will have to hope that Tim Kaine is proven right and that those critics are proven wrong.