If Iran can shoot down a US drone in a fuzzy border area, they are likely to react more viciously if attacked directly. Trump’s Generals most likely estimated that such an attack would trigger an all-out-war, something they are not yet prepared for. Despite the posturing from the United States, Iran has the capacity to deliver a few humiliating blows in the first stages of a conflict before the US summons all its resources. And again, it is almost a certainty that Iran is benefiting from valuable reconnaissance intelligence provided by its allies.