Brett H. McGurk (born April 20, 1973) is an American diplomat who was appointed by President Barack Obama on October 23, 2015 as Special Presidential Envoy for the Global Coalition to Counter ISIL and was retained in that role by the Trump administration. He replaced General John R. Allen to whom he had been a deputy since September 16, 2014. He also served as Deputy Assistant Secretary of State for Iraq and Iran, at the U.S. Department of State, and from October 2014 through January 2016 led 14 months of secret negotiations with Iran that led to a prisoner swap and release of four Americans from Evin Prison in Tehran, including Washington Post journalist, Jason Rezaian. This assignment, among others, reinforced McGurk's "reputation as a doer", according to the New York Times. He earlier served under President George W. Bush as Special Assistant to the President and Senior Director for Iraq and Afghanistan, and under President Obama as Special Advisor to the U.S. National Security Council and Senior Advisor to the U.S. Ambassador to Iraq.
McGurk served as a law clerk to Chief Justice William H. Rehnquist on the U.S. Supreme Court during the Court's 2001 October Term.
On December 22, 2018, in the wake of President Trump's decision to withdraw troops from Syria, McGurk announced his resignation from his post effective December 31, 2018. He had been slated to leave the post in mid-February 2019. Wikipedia