Well, it's kind of complicated, actually, and I think a lot of it might be specific to my world. Long before that time frame, the U.S. became really fixated on genetic engineering- they thought certain negative personality attributes could be found in a person's genetics and that by altering the genes they could completely get rid of traits like criminality, violence, etc. The thinking is rooted in the Eugenics movement which took place in this world too. Anyway, it was basically a terrible disaster. Allegedly, the people they did the genetic testing on were really messed up, and a civil war followed between the people who'd had their genes altered and those who hadn't. Then the government set up these social experiments in different cities where they cut the population off from the rest of civilization and any sort of information about the outside world and the country's past, let them develop their own culture and way of thinking, and then observed things using surveillance cameras, hoping that they'd come up with some way of life that would undo the damage from the war and the genetic engineering. In 2164, that system fell apart, because people from one of the cities found out what was going on. The government branch responsible for all of that was basically taken down, so the experiments couldn't really continue anymore. By and large, the country still remained hung up on the concept of 'pure genes' and 'damaged genes' (which is really a load of bull shit, so I won't bother going into that, but the former have privileges over the latter), but Chicago, which had been a part of those social experiments, rejected these notions of genetic superiority and inferiority and runs under a different law system. It's still a part of the U.S., just laws concerning employment and education and things like that are different, and this model has started to spread to some other cities.
I don't know if that explanation really makes any sort of sense to someone from a different place. Part of the problem is it's all kind of convoluted what happened to begin with. So what was Asia like? Is it different from its history in this world?