It's almost a given that post-cold war Americans are unable to negotiate from level playing field or when they are at a disadvantage. If they feel like they can't squeeze the other party without themselves getting burned they will just keep flinging shit however impotently. It's really something to do with geography. USA has two oceans to the east and to the west and to the north and south relatively weak subordinate states. Leadership feels no pressure to set the world on fire if it benefits them, they themselves live on an island and will always be more or less be isolated from any chaos. As long as US sits on enough global economic choke points and retains a superpower status they don't have to keep any promises either. They only thing that can threaten this model are nukes reaching US mainland, alternatives to dollar or domestic uprisings.