Iran is broke and the mullahs hang onto power by their fingernails.
President Trump is bleeding them dry. Slowly and methodically. His supposed inaction is itself an action. If he gets a second term the mullahs will fall, and the Iranian people (who for the most part are free thinking western values oriented people, notwithstanding the autocratic regime they are forced to live under) will be free. If so, history will judge this as his greatest achievement.