One of them.....maybe.

I would say, most likely , but a world quite different to what we have now.
Human society is experiencing an accelerating exponential rate of change and has been for quite some time.
Population alone is freaky.

Yes as things change and they will the USA will again be a dominate power most likely with China which is developing rapidly.

Yes we will, We will become progressive in ideology and will combine with Canada to make North America the technology and science center of the globe. Artificial intelligence is good as an aid but the artificial intelligence of a republican is just not the same type of artificial
We as a nation will once embrace science and technology producing a more wonderful globe to live on. In fifty years we will see the tea party and alt right as our dark age.

No... artificial intelligence will be in charge. It will be the aliens. We will have the terminators. Its possible. The computer only took 30 years to turn into what it is. ...lol.