With a PoD after 1788, have a US state consisting entirely of one city (optionally with suburbs/hinterland). It can't be Washington, DC.
I don't see why...I'm not sure that's possible. It'd require an amendment, if possible.
Just gibe it half a century, it really will be that.If hinterlands count, Rhode Island is pretty much this IOTL; the entire state is in the greater Providence metropolitan area and the entire state besides the town of Westerly is in the Providence-Fall River-Warwick NECTA.
Rhode Island resident here - not really. You could assume a city of Greater Providence that includes Warwick, Cranston, Johnston, and Conventry all part of Providence (I don't really see any difference between the cities myself and wouldn't mind the cities merging into 1), but Woonsocket, Westerly, Kingston, Warren, Bristol, and Newport are definitely NOT part of Providence.Isn't that Rhode Island?
You only need the extraordinary constitutional measures if you're carving the city-state out of an existing state.
Their are no 'extraordinary constitutional measures' involved, the Constitution very clearly states that a new state can be formed from the territory of one or more existing states if the legisltures of the state(s) affected agree and the Congress agrees.