TEHRAN — US President Donald Trump's announcement that the US-Iran memorandum of understanding is "over" appears, at first glance, to mark the collapse of the diplomatic opening that briefly emerged after last month's ceasefire. 

Yet Tehran's response so far suggests a more nuanced calculation. Rather than acknowledging the death of diplomacy, Iranian officials are portraying Washington as the party that abandoned the agreement, while allowing the Islamic Revolutionary Guard Corps to demonstrate that any US withdrawal from the deal will carry military costs.

Although the overnight exchange of strikes on Wednesday has pushed the two countries closer to direct confrontation than at any point since the war ended, Tehran's messaging indicates it has not entirely shut the diplomatic door. Instead, the balance inside the Iranian ruling system appears to be shifting, with military coercion increasingly shaping the environment in which diplomacy operates.

Trump left little ambiguity at the NATO Summit in Ankara. "As far as I'm concerned, it's over," he declared about the ceasefire after US forces struck more than 80 targets in southern Iran following attacks on commercial shipping in the Strait of Hormuz. While he added that negotiators could continue talking, Trump dismissed further diplomacy as "a waste of time."