William Pelham Barr served as the 77th U. S. Attorney General from 1991 to 1993 during the first Bush administration. He is a member of the Republican Party. He wrote a 20 page memo to the DOJ arguing that Article II of the Constitution gives the president the power to appoint and fire certain people. Therefore, the president cannot obstruct justice by firing Comey. His memo is limited to the people he appoints and fires.