They are mainly using the known fact that there's no chance in hell that the US will invade Iran with ground forces. They also previously negotiated as if this war would never start, so they might make a mistake as this is Trump after all.

In any case, Iran is not in a prime position either, it has many economic assets that can be completely destroyed as it has no air defense and then leave them in a much worse situation, while the only real damage they can do to the US is by attacking their own neighbors