(Zach D Roberts/NurPhoto/Sipa via AP Images) Sean Hannity during the Conservative Political Action Conference on February 23, 2017, in National Harbor, Maryland S ean Hannity, host of an eponymous Fox News prime-time show, is said to be one of President Donald Trump’s closest advisers. In fact, he’s known around the White House as “the ‘shadow’ chief of staff,” according to Washington Post reporters Robert Costa, Sarah Ellison, and Josh Dawsey. He’s also a client of Trump’s tarnished personal attorney , Michael D. Cohen, now subject of an investigation by the U.S. attorney in the Southern District of New York. After Fox was caught by surprise by that fact, which was revealed in a Manhattan court room, the network’s executives issued a statement saying that Hannity “continues to have our full support”— despite the fact that Cohen had been a guest on Hannity’s show with no full disclosure offered of their attorney-client relationship. Every night, Hannity reaches an average audience of...