Fortune Favours the Bold

I’m no expert on the US constitution as I’m a Canadian, but wouldn’t a president, that confirms himself as a king, going against the constitution itself, invoke some kind of martial law where the military steps in to remove him from his position?

Isn’t this the sort of thing the U.S. constitution was setup for? To fight the Tyranny when someone tried to overthrow the system and laws upon which they were elected to uphold?