Timothy O'Brien: Trump tried to fire Mueller. He'll try again.

U.S. President Donald Trump arrives during the annual meeting of the World Economic Forum in Davos, Switzerland, Friday, Jan. 26, 2018. (AP Photo/Markus Schreiber) Last summer, the president of the United States, who is the nation’s chief law-enforcement officer, tried to fire the federal appointee overseeing an investigation into whether the president or his advisers had broken the law by, among other things, obstructing justice.

When Donald Trump angled for Robert Mueller’s head last year, according to a report from the New York Times, he reasoned that he was within his rights because the special counsel had too many conflicts to impartially run the Justice Department’s probe of possible…