European diplomats have been lining up to urge the Trump administration to stay in the deal. They're nervous that an anti-Iran current in Congress could eventually spoil the agreement. And they worry that if the U.S. exits the deal, it could try to punish the companies from Europe that are doing business with Iran.
For now, they can go on developing things like aircraft, auto and oil deals with the Islamic Republic. And Trump's threats have drawn attention to the possibility that Europe and Iran could just continue with the deal and without the U.S.
European countries have shown some more willingness to consider other actions to pressure Iran to rein in its hardliners. That could be because of Trump's threats to scrap the deal.
Threats for future steps may have more impact than anything else Trump did on Iran this week. By staying in the deal, he keeps those threats alive.
And that means Trump can continue to raise Iran as an issue, as he did throughout his campaign and since taking office. That goes over well with his supporters, especially those who recall that the Iran agreement was a hallmark of the Obama administration.
"In the event we are not able to reach a solution working with Congress and our allies, then the agreement will be terminated," Trump said Friday. Considering his efforts to dismantle other Obama legacies like Obamacare or leniency for undocumented child immigrants this could be a step toward eventually pulling the U.S. out of the Iran deal.
Or it could remain a threat, while Trump carefully pairs his denunciations with careful measures to keep the deal in place.