I suspect trump is now at the point where if he was in fact impeached by House and Senate he would simply say: “OK. Come enforce your silly writ. The executive branch will still follow my instructions on my personal say so”. And he’d probably be right in that.
At the end of the day, the guy who controls the guys with the guns rules the country. Any country.
And also for sure that would be close to the end of the USA’s current system of government.