Threateninv a civil war isn't a partisan issue. I believe we need to go all the way back to Andrew Jackson to think about a time where a president is openly threatening it's own US cities. The Civil War under Lincoln was provoked first under the confederate states. I legitimately can't think of anything more recent than that, no matter the alignment.
We can talk about warmongering, but you just don't threaten your own people. At least not until they threaten the government. Because provoking and. attacking the people you lead is just profoundly stupid. There's no rebellion to quell, no land to annex. It's just a man pretending to be a dictator in the stupidest way possible.