In the late 20th Century, unprecedented immigration changed completely the cultural foundations of the United States . As new majorities took over, a counter migration began as Americans moved back to ancestral countries. By 2038 the country had a new demographic make up, so Congress empowered a Constitutional Convention to decide the future composition of the country. Some states chose annexation into Canada, Mexico, or Caribe, while others combined into new countries. In 2040, the United States was dissolved by Congress. Another event of the time was climate change that caused most of the United States to be drought-stricken, except the Northern Appalachian region where the United States constructed a huge artificial aquifer. By 2050, Atlantica, a new country, controlled the aquifer, and