I got a first-hand report that far north of the Mason-Dixon line many Trump supporters are displaying  the Confederate flag. Do they favor secession from the Union? 

Apparently so: Trumpians want not just the southern states, but the entire country, to secede from the Union, to abandon everything America has stood for. They’re eager to reconstitute our nation into a new confederacy, a proto-fascist state. So it would seem, though I doubt if their thinking has advanced that far. They are prisoners of their resentment. Displaying the confederate flag is their way of expressing it.