South Korea’s President tried to do that a few months ago and the military had to arrest them.

If the President violates the law, and Congress impeaches and convicts them, and they don’t peacefully step down, and the military/police does not remove them from office/sides with the President, we effectively have a coup and the United States as outlined in the Constitution ceases to exist.

> the United States as outlined in the Constitution ceases to exist.

As the risk of deflating your apparently boundless optimism, that ship has sailed. The idea you have of a country operating under the rule of law is not congruent with reality.

They wouldn't have to - the VP would become the President and therefore the CIC. He would instruct to military to remove the former president. If the VP does not oblige, he can be impeached as well and the Speaker of the House would become POTUS.

At that point, being the ones with all the guns, it would fall to the military to decide who they are loyal to: the Constitution, ex-POTUS, or themselves, and they will act accordingly.