US backers of the Iran nuclear deal are increasingly confident of enough Democratic support to ensure it survives review by Congress, despite fierce opposition by majority Republicans and a massive lobbying drive.
By the time the House of Representatives recessed for the summer last week, no senior Democrat in the chamber had come out formally against the agreement and several central figures, including Minority Leader Nancy Pelosi, were strongly in favor.
Pelosi said she was confident that if, as expected, Republicans pass a "resolution of disapproval" to try to sink the deal, a promised veto of that measure by President Barack Obama would be sustained.
At least 44 Democrats in the House and 13 Democrats in the Senate would have to defy Obama and join Republicans in opposing the deal to get the two-thirds majorities in both chambers needed to override a veto.
"More and more of them (House Democrats) have confirmed to me that they will be there to sustain the veto," Pelosi told reporters.
The United States was the prime negotiator in the July 14 agreement between world powers and Iran to curtail Tehran's nuclear program in exchange for lifting sanctions, and its engagement is essential for implementing it.
In the last two weeks, the White House has rolled out its big guns at congressional hearings and private meetings to advocate for the deal, which Obama says is not perfect but is the best way to keep Iran from getting a nuclear bomb.
