As Congress's vote on a resolution to disapprove the administration's nuclear deal draws ever nearer, the math for President Obama is looking better and better.

The magic number of Senate supporters the president needs to ensure that the deal stands is 34. Currently, he has 30. So he needs to pick up just four more to preserve the agreement — and there are still 14 remaining undecided Democrats in the chamber, several of whom have already made positive comments about the deal. So Obama has a lot of options.

And tellingly, after a month of intense criticism of the deal from the right and from pro-Israel groups, only two Senate Democrats have been swayed to oppose the deal so far: Sens. Chuck Schumer of New York and Bob Menendez of New Jersey. They'll be joined by, it appears, every single Senate Republican.

But that wouldn't be enough to sink the deal. If opponents want to block the sanctions relief that's crucial to the agreement, they need to assemble a two-thirds majority in both the House and the Senate that can override a promised veto from Obama. And that's impossible to reach without a lot of Democratic votes, as I wrote in July:

Deal opponents once hoped that the agreement would become politically toxic, leading to many Democratic defections. But that hasn't happened. Instead, the key swing votes — including some of the most conservative Democrats in the Senate, like Claire McCaskill and Joe Donnelly — have been won over by the administration.

The state of play in the House is tougher for outsiders to gauge, but opponents appear to be well short of the 44 Democratic opponents they need there — just 14 Democrats have said they'll vote to kill the deal, according to the Hill. Again, the deal's opponents would need a veto-proof majority in both the Senate and the House to keep the sanctions in place.

According to a Friday report from Eli Lake and Josh Rogin of Bloomberg View, deal opponents have already resigned themselves to losing the vote eventually. Furthermore, they write, "Many Republicans now acknowledge in private that they were handed both a political and a policy defeat on the nuclear deal."

The new fight is just symbolic

Now that the deal looks so likely to be upheld, the new question is whether Democrats can save President Obama from having to veto it in the first place.

There wouldn't be any policy stakes here — achieving this would simply save the president from the embarrassment of Congress passing a resolution condemning his administration's foreign policy.

For that to happen, 41 Senate Democrats would have to vote to filibuster the GOP's planned disapproval resolution — meaning Obama would need to win over 11 of the remaining 14 undecided Democrats in the chamber. That's a tall order, but given that only two Democratic senators have opposed the deal so far, it doesn't seem completely out of the question.

These are the undecided Senate Democrats

The vote will likely take place in mid-September. But if you want to keep track yourself beforehand, here are the remaining undecided Democratic senators. Again, the administration needs to win four of their votes to uphold the deal, and 11 for a filibuster that would make a veto unnecessary: