> But what does the U.S. get from this $3 billion a year, besides a
> more difficult and prickly relationship with the Gulf states where
> the oil is?
That's a post-Cold War question, but we're talking about the history of the Cold War era. Capitalist empires don't "get" things from their proxies the way the Romans plundered their provinces. There's a different rationality at work, namely classic good-cop, bad-cop strategy: the minor powers serve as the attack dogs, gendarmes, and errand-runners, so that the hegemon can relax and watch NFL football -- what Bourdieu would call the symbolic capital of hegemony.
Put more sharply still, you'd have to explain why the US *didn't* invest those billions in R&D, or energy conservation. The answer isn't stupidity or some evil conspiracy of brain-eating aliens, but objective history: a decrepit, enfeebled 18th century system of governance and the narrow and self-destructive class interest of the ruling elites of the US.
-- Dennis