Democrats and their media allies are again shouting “constitutional crisis,” this time claiming President Trump has waded too far into the Russia investigation. The howls are a diversion from the actual crisis: the Justice Department’s unprecedented contempt for duly elected representatives, and the lasting harm it is doing to law enforcement and to the department’s relationship with Congress.

The conceit of those claiming Mr. Trump has crossed some line in ordering the Justice Department to comply with oversight is that “investigators”...