With the entire international community having ruled out negotiating a new P5+1 nuclear deal with Iran including the terms President Trump wants, the administration’s strategy has focused on trying to get the US Congress to impose the changes within US participation in the deal.
This includes expanding US threats of “snap back” sanctions into myriad behaviors totally unrelated to the nuclear deal. No one else would respect these US demands, but it would give President Trump some claim of Congressional support for imposing sanctions in violation of the pact.
It’s not clear President Trump will be able to push this through Congress however, especially in the Senate,where trying to get 60 votes is going to involve courting Democrats. There weren’t a lot of Senate Democrats with a problem with the deal in the first place, and among those who voted against it in 2015, many are openly critical of trying to go back on it now.
It’s not clear that Republicans in Congress are as uniformly against the deal as they were in 2015 either. Analysts have been warning for months that the US trying to back out of the deal now would leave the deal intact and the US international isolated.