Energy

Some Pinko Neckbeard College Professor, 40 years from now...  I predict this theory will become all the rage in the Ivory Tower...  will posit that the US only got strong during the early-middle part of the 20th C, and again in the mid 21st, because we were blessed with an abundance of natural resources, particularly fossil fuels.  And that the only time our power ebbed was in the later part of the 20th Century when we became a net importer of oil.

This theory will infer that mere chance presented us with out wealth, that any other factor is not just inconsequential but infinitesimal, and that thusly, it is unearned and we should redistribute our power and wealth further as if we hadn't already been doing that for decades. 

This selfsame professor will overly credit any Mid-East power during the US's so called ebb.

I don't think the Socialism impulse will ever die, no matter how many stakes we drive through its heart.