Our election was corrupted, our democracy assaulted, our sovereignty and security violated. This is the definitive conclusion of special counsel Robert S. Mueller III’s report. It documents a serious crime against the American people. The debate about how to respond to Russia’s “sweeping and systemic” attack — and how to hold President Trump accountable for obstructing the investigation and possibly breaking the law — has been reduced to a false choice: immediate impeachment or nothing. History suggests there’s a better way to think about the choices ahead. Obviously, this is personal for me, and some may say that I’m not...