What Does It Take to Remove a President?

I don't blame President Donald Trump for his angst and bitterness over his impeachment by the U.S. House of Representatives. In his mind, he has done "nothing wrong" and not acted outside the constitutional powers vested in him, and so his impeachment should not have come to pass. He believes that the president can legally extract personal concessions from the recipients of foreign aid, and he also believes that he can legally order his subordinates to ignore congressional subpoenas.

Hence, his public denunciations of his Senate trial as a charade,...