President Trump has unleashed new weaponry in his war against Democrats, liberals and the left. Over the past four weeks, he has initiated what amounts to a unique form of partisan civil war designed to amass power in a nominal democracy and defang, decimate and defund the opposition. Trump’s assault on the left combines the use of the available tools of violent conflict — the military, the Department of Homeland Security and ICE in particular — with the prosecution of critics (and people he just doesn’t like), cuts of essential funds for liberal institutions, the use of regulation to threaten...