" If nothing else, televised hearings would demonstrate that Mr. Trump not only lacks respect for the rule of law, but for Congress and the separation of powers — a fact that, in and of itself, is an impeachable offense.As Nixon learned, Congress will not abide a president who defies its subpoenas. If the present moment has yet to offer any similar profiles in courage, that does not mean we will never see dramatic conversions. This early in our current process, it is a mistake to presume that no Republican lawmaker, House or Senate, will ever have a crisis of conscience and vote against Mr. Trump. And it is even a bigger mistake to let that presumption influence whether an impeachment process should be initiated or not. "