Israel - Rwanda - Croatia

I think the US prefers dealing with militaristic and beleaguered states for clients.  The more potential enemies they have the better.  A mauling or two helps set the tone for the alliance,  remembering always that there are no friends but merely opportunities. 

It should also be remembered that of the US's strategic allies,   the Somoza regime fell in Nicaragua due to a civil war,  the Shah's Iran fell due to a civil war, the apartheid era white South African rule fell due to political, economic, social and guerilla pressure. 

KR