Yeah I did wonder myself if that tweet was an admission of guilt.

If I were a lawyer responsible for defending Trump in the Hague, I'd argue that the tweet was actually an abbreviated way of saying "If Iran does not comply, we will destroy all military assets, including but not limited to their ICBMs, Bridges, and Power Stations, such that we have total military dominance."

Now very obviously (to me at least) this was not the intent of the message, but I don't know whether you could prove that in a hypothetical war crimes trial.