Time for even more references to Thomas Schelling. Do you want to understand what is going on with Trump and Iran? Read The Strategy of Conflict already. Don't I reference it enough?
Schelling wanted to explain nuclear deterrence. Imagine two people, bound together on the edge of a cliff. One threatens the other: I'll jump if you don't do as I say! Makes no sense, does it? They both die if either jumps. On the other hand, imagine a gently sloping hillside that gets steeper. Threatening to take a single step down the slope doesn't guarantee death. It just incrementally increases the odds that they slip. Incrementalism. Inserting randomness into the process. These are key elements to Schelling's argument about how deterrence can work. The gradual escalation of conflict to the point that someone panics, slips up, and simple human error throws the conflict out of control. The threat to take such a step is credible. The problem occurs when that credible threat is carried out precisely because it is credible.
We are seeing gradual escalation with Iran right now. Trump is making threats. Iran is ignoring them, and continuing to conduct missile tests. As Schelling would say, each side is taking incremental steps down a hillside that gets ever-steeper.
Worst-case scenarios here are pretty bad. And that's before we talk about the Trump factor.