Since were talking about secession, wouldn’t be enough for the coastal and lakeside large cities of Los Angeles, San Francisco, New York, Seattle, Boston, Portland Oregon, Philadelphia, Miami, Chicago,etc to form city states and leave the Union.
Well no, the political division of the state, which has a legislature and can act independently, is the next logical political unit that can emancipate itself legitimately from DC. After that, what happens in the newly formed country(s) would be up to them.