Carolina fiction

This listicle is a super rough idea, and not a cohesive listing of any lore. That might come later but probably not, this is mostly a creative exercise for me

• After the federal gov't falls into turmoil, the states gain powers and responsibility (i.e. the US Army is now entirely made up of state NGs, which only answer to each governor; each state has citizenships and passports of their own issuing, etc)
• Various states begin joining together into smaller unions; a (North) American Single Market begins to form (mostly out of the States; but since it's unbundled, Canada and Mexico are in talks to join)
• The American Interstate Congress forms, which is a quasi-legislature which functions similarly to the European Commission. All of the existing states are members of this Council, and each one elects its representatives (not completely sure how these would be counted; maybe the bicameral system is kept). As for what counts as a state, it mostly uses the original states, but the member nations can opt to change this. (i.e. NC and SC are represented separately in the Congress, rather than as Carolina)
• NC and SC decide to coalesce into Carolina (full name may be below), and form a new capital city, tentatively Carolina City (NC and SC are both states of the new Carolina)
• The Interstate Congress manages agreements about passport validity and free movement between member nations; so it's similar to the Schengen Zone, except binding to all of the Congress's participating states.
• Interstate Congress member states (nations) are able to withdraw their participation at any time. This also withdraws the support and protection they get from other member states as part of the AIC agreements.

Other changes which occur, which may be unrelated to this vague idea:

• Oregon, Washington, and maybe Idaho join to form Cascadia (not sure if it would have a full descriptor title or not).
• California may incorporate Nevada. Maybe that's just me thinking they're "similar enough."
• Some of the Great Lakes states might join forces as well? Wisconsin, Michigan, Illinois mostly
• Alaska probably becomes a province of Canada. Maybe Russia takes it somehow though idk

The Republic of Carolina

• Flag incorporates Carolina blue: the light-blue used by the Carolina Panthers and UNC (well, specifically the Panthers blue because it's more visually appealing imo)
• Capital is Carolina City
• Split into north & south at the historic state line (maybe east & west are divided as well? particularly in NC they seem to have a very distinct identity from the central parts of the state)
• Maybe I can hope for intercity high-speed rail? The NC line I have already drafted up; a line connecting the state capitals to each other and Carolina City; maybe an SC line but I'm too unfamiliar with it to make it

Carolina City

• An intentionally-planned city similar to DC, except that it has a "government district" that specifically only has residences for government officials, and government offices, and is controlled by the Carolina government instead of the City government
• City flag closely based on that of Carolina (inverted colors? includes the flag in it somehow?)
• Located in that obvious 45 degree angle between the state borders (which is where the gov district would be) maybe stretching to the Pee Dee River for precious water? Near NC/SC 38
• In unified Carolina, it is a city-state (Charlotte & Myrtle Beach might also get this treatment)
• Sufficiently dense, loosely zoned, and please for the love of god use this opportunity to put in a ton of mixed use retail-residential zoning (and some retail-office, but much less of that)