There have been some comparisons with Scotland though Scotland had a long history as an independent nation before union with England in 1707 and has retained its character as a nation since then in many ways, both politically and culturally, despite being fused into the UK. I know that Texas once was an independent nation for a short time however, from my limited perspective across the pond, its people seem to share substantially the same culture and common national identity with the rest of the USA. Is it fair to say that differences are really no more than regional?
Of course, a big enough and powerful enough region can secede if it wants, irrespective of the usual list of criteria for nationhood. But would Texans be content enough if the rest of the USA did more to acknowledge their special identity, and cause desires for independence to subside?