This decision by Trump is also playing into Russian hands. Even though Russia and China are parties to the Iran Nuclear agreement, Russia clearly sees it in their long range interest to see a weaker Western, NATO Alliance. This unilateral decision by Trump to pull out of the agreement throws a monkey wrench into commerce between and among the U.S. and the NATO countries and plays right into Russian Hands. I wonder if Trump received encouragement to pull out of the agreement from Russian interests. I wouldn't be at all surprised if that were the case simply because it makes no sense at all from any other perspective. He went into his campaign bad mouthing the Iran Deal and lying about it to his supporters. Making up facts, as he habitually does, to justify the unjustifiable. He must have been kowtowing to the Russians all along, which would make this latest move just a fulfillment of a promise he made to them in return for support provided by Russians to his campaign. Surely the Russians have enough of the missing pieces to his collusion with Russians to send him to the big house for a very long time. He must feel the pressure. He must be scared as shit as the walls keep closing in on him..
When you start analyzing Trump's moves since his inauguration you see a pattern of furthering Russian interests. Congress interfered a bit with his plans to lift the trade sanctions on Russia, but he was able to put implementation on the slow track. The Constitution wisely gives The Power to Negotiate Treaties to the President, but that backfires when there is a criminal like Trump in the White House. There is little Congress can do, in the way of direct action, to stop him from wrecking the Iran Deal, even if Congress had the will to. His action is, however, going to hurt U.S. corporate interests . Let's see what Trump has up his sleeves as a way to get around that.