In a healthy society, you wouldn't have this type of thing. And in a healthy society the US army would not invade as there would be A Rifle Behind Every Blade Of Grass. When there's a functioning social contract and everyone's kind of on the same team, you don't want to invade because you will find everyone on the same team...
A country with no social contract where the presidency is fought over and held by force becomes a pushover for any foreign army that would like to own it, consider for example Venezuela.
