Lore:

In the 2080s, after several decades of stagnation and dysfunction, Texas finally decides that it wants to secede under the tenure of an unpopular Democratic Socialist president. The Federal Government decides that it will actually grant independence if they win a referendum, which Texas holds and delivers a "yes" majority, causing Texas to be the first state to ever successfully leave the Union.

The president's popularity plummets and during the next election a far-right candidate wins. With the legal precedent of states leaving the Union established if the federal government consents, the new President embarks on a program to deliberately alienate the most liberal states by embracing far-right polices and identity politics, so as to create a country composed of only "true Americans." He counts on Texas rejoining this reduced United States as well.

The West Coast bolts, as does New England and New York. The plan backfires when states he wished to retain, such as Pennsylvania and Virginia, start agitating for independence too, refusing to offer federal consent to referendums there. Several of these states do so unilaterally, and the president responds by sending in the army to forcibly break up the illegal referendums. Things spiral out of control, federal troops are shot, several states unilaterally declare independence, and the whole country goes into civil war mode.

This is the result several decades later.