(Please see the 5th graph down at my friend Stuart Staniford's excellent blog. Crude and condensate, the stuff we make transportation fuels out of, has seen no growth in production in spite of large price incentives. While it is true that there is a long capital investment cycle... it ain't this long. Of course, there has been a large increase in NGPL's... that's nice for the petro-chemical industry, but it doesn't do a thing for transportation fuel... well, except for propane vehicles... and ethanol's 2 million bpd might, MIGHT, have a million bpd left to go... and then again, it might not. Peak Oil is here... and even if the inevitable decline in production is not... that decline in availability is here for the U.S.)
In the final analysis on Oil supplies - and hence the U.S. economy - its all about the rate of change. As for the politics and economics of it all... Political upheavals sometimes lead to very positive outcomes, and in this regard I am rather more optimistic for America.