Credit yes. But decisions and strategy for this were made before Trump became President (as were some bad decisions)). As an example, the capture of the oil field was by our allies and not us. The key decisions and leadership were the arming, choosing, and keeping of allies at the risk of the rise of Iran in Iraq, the strained relationship with Turkey as we allied and armed the Kurds vs ISIS in Iraq and Syria.  Now comes the hard part of decisions and leadership for Trump, as we jockey with everyone in the region and risk the rise of Iran and Russia if we cannot win and maintain leadership in the region. It will test Trump’s choice to arm and ally with the Saudis. Meanwhile, Trump faces the increasing rise of Muslim extremists, including ISIS in several places in Africa where Mattis and the military have begun increasing US troops as Trump assumes leadership of a new frontier there with new Muslim leaders to up This region where Russian and China have interests will test him.