It’s all hypothetical until a final deal is reached, and some Democrats privately believe the president or Republican leaders might try to find a way around a congressional vote if they can. The Democratic aide said that “any other agreement related to Iran would likewise need to be submitted under the Case Act,” a reference to a 1972 law that requires the secretary of state to submit international agreements to Congress.

And not all Republicans are opposed to some level of scrutiny. Sen. Lindsey Graham, R-S.C., called a congressional review a “sound way forward” this week. Senate Republicans also previously warned former President Joe Biden that any agreement he reached with Iran during his term would be subject to the 2015 review law.

Trump and his officials should be confident they’d be able to withstand congressional scrutiny in any case: The bar is high to block any agreement under the law.

Senate Democrats’ successfully stopped a disapproval resolution in 2015 — and even if it had passed Congress, the measure would have needed a veto-proof majority to override the president. Even so, it could be a painful exercise for the president’s party: Four Senate Democrats defected on that vote a decade ago, including Sen. Chuck Schumer, D-N.Y., now the minority leader. And supporters of the deal had to work hard to limit further defections.

Shelby Talcott contributed to this report.