America's foreign policies are, as is pretty much every other actions taken by the USA driven by the owners of their industrial power base. War equals arms equals expenditure equals fat order books equals PROFIT !
Of course, having then destroyed their enemies capability to resist by bombing their industries and destroying their armed forces, the USA then bids for ( and by dint of bribery and corruption inevitably secures them ) the contracts for rebuilding and restoring the infrastructure of their erstwhile enemies.
All of the above makes even the inevitable oil rights that they will then demand,
almost small beer by comparison !