The US military has taken foreign volunteers since the Revolution, this is hardly breaking news.
I know a guy who was in one of Ayatollah Khomenei's Angel Martyr battalions, when he was 13, him and a 12 year old actually killed an Iraqi tank, it took two of them to lift the RPG launcher, who enlisted and served in the US Army later.

__________________
“ The subjects of every state ought to contribute towards the support of the government, as nearly as possible, in proportion to their respective abilities; that is, in proportion to the revenue which they respectively enjoy under the protection of the state.”

Adam Smith , The Wealth of Nations 1776

"We have always known that heedless self-interest was bad morals; we know now that it is bad economics"
FDR's second Inaugural Address