Well mate how I understand how it works is that alot of the money you "gift" to Nations has conditions attached, now some of these conditions
include money must be spent on infrastructure and US companies must be utilized in these constructions/development and hence it means jobs indirectly
for American Companies and the money finds it way directly back to the USA.
Read Confessions of an Economic Hitman and it all makes sense, besides you realize they just create your money out of thin air anyways ?

