I wonder what the IQ of the U.S. will be in a 100 years when that nation is
majority non white?
Many cities and towns that had no crime, drugs, gang problems fifty years ago
are now full of crime, drugs and gangs.
I wonder if the U.S. will still be a super power in 50 years?
I doubt it. Without addressing whether that's a good or bad thing (irrelevant), there are a number of reasons for this.
For one thing, native-born Americans (especially white Americans, those of European descent) aren't reproducing at replacement levels. Population increases are due to immigration, and first-generation immigrants whose culture still encourages large families. These people are largely Hispanic, but an emerging subset are Arab -- specifically Mohammedan Arabs.
As Matthew noted above, Arab nations aren't exactly among the smartest in the world. I wouldn't suggest that it's genetic, although it could be. It's certainly due in good measure to a culture -- a religion, let's be honest -- that oppressively crushes any form of independent thinking, let alone outright creativity. Mohammedans simply aren't allowed to do any intellectual
exercise. Since they
are reproducing well above replacement levels (3.1 globally; I can't find figures for the U.S.), it follows by extrapolation that in 50 years, as you suggested, the American ethnic profile will likely lean in their favor.
What about those non-Mohammedan Americans of European descent? They're reproducing at a rate of only about 1.8 (according to Pew), a solid three points below replacement value when factoring for infant mortality. This is simply what 40 years of Roe v Wade and a contraceptive culture (going back a lot further) have wrought.
Of course, once they reach critical mass, they'll make their power grab, and we won't have elections to worry about. By then (100 years, you say?), the "average IQ" won't matter.