A "What if" for Wednesday

This week I read a blog post from Scott Adams, about good news, which contained as its first item the suggestion that America might be close to reaching fuel self-sufficiency.

This crossed over nicely with what I've been reading for work. Now in my fourth year of teaching 20th century US Foreign Policy to my oldest students, I am really getting into it, and have started reading a wider variety of books than Ian has provided. My favourite of these so far is the very readable Rise to Globalism: American Foreign Policy Since 1938, by Stephen E Ambrose (helpfully available on my Kindle). In it, he posits that, in spite of winning the Cold War, America was more vulnerable by the 1990s because it was so dependent on the Middle East for its fuel needs. He suggested that, without this dependence, America might have returned to its isolationist ways of the early 20th century; and, indeed, was doing so until Iraq invaded Kuwait.

I have a few holes to pick there but let's ignore them for the purposes of this extended ramble. If America really did achieve fuel self-sufficiency, what impact would that have worldwide?
What impact would it have on the Middle East? And on petrol prices?
Would all US military overseas just pack up and go home, and what about the countries they are supposedly helping?
Would they maintain their alliances, and membership of things like NATO?
Would the miltary-industrial complex in the US allow America to reinstate isolationism? The defence budget pre-1939 was less than £500m, with 185,00 soldiers. Now it's £300b*, and countless personnel. That's an enormous number of jobs and businesses. Also, when you think of it like that, you can understand why people come up with conspiracy theories about 9/11.
Who would fill the power vacuum? China?
With America more reliant on natural energy, what would happen to global emissions? Would there be more effort made to develop alternative car/plane fuels? Unlikely, I think, as long as somebody's still making money from the oil.

Just thinking, you know. I like it when I've read enough on a subject to finally form an opinion. Teaching this last year, it was all about fear as a motivator, but now I've read more and concluded this is just a facade. I'll continue to read and eventually decide what's behind it, I suspect.


*My favourite way to think of big numbers like these is in seconds. 500m seconds is around 15 years. 300b is around 9,600 years.