The Senate impeachment trial of President Trump ended not with a bang but a whimper. What different outcome could one expect from a trial without so much as a single witness, a single document, any cross-examination or a defendant respectful enough to show up? Law students are taught early on that a trial is not a grudge match or an ordeal; it is a search for the truth. Trial lawyers know that cross-examination is the most effective truth-testing tool available to them. But the search for the truth requires witnesses, and when the command from Senate Republican leaders came down...