By 2420, the United States of America has lost most of its territory and is now relegated to a corner of Colorado. it reforms its government in the form of the NAR. However, it still ranks well regionally in terms of military and economic power. But it is newly committed to an insular foreign policy, seeking no more territory and instead developing upwards and down into the earth.
The Denver International Airport is the crown jewel of the country, the foremost Air/Spaceport on the continent.
Cheyenne Mountain Complex is a massive fortress, thought to be impenetrable.
Colorado Springs is a semi-arcologized city with well-maintained Carbon Macrofilters and habitable air.
The emergency measures taken for Continuity of Government created a powerful and efficient command economy that has lasted to the present day. A consortium of private interests controls the civilian government which has nominal control over the military, but the emergency measures that empowered the military to unseat the government have not been rolled back.
The upper classes in the US are called Cogs, derived from "Continuity of Government." Only those military, government, and business leaders deemed important enough to save were evacuated to Cheyenne Mountain Complex, so the ruling class is relatively broad here. The natives of Colorado Springs & other towns were also frequently government workers or contractors. Economic inequality is massive here, but the welfare state has been expanded to ensure that no one goes wanting.
That's not to say the Cogs are necessarily benevolent leaders. They just hate the sight of poor people, and consider the preservation of Colorado's environment part of their American birthright.