Self-Determination and Secession Under International Law: The Cases of Kurdistan and Catalonia
Introduction Kurds held an independence referendum on September 25, 2017, deciding by an overwhelming majority that they wished to separate from Iraq and form an independent state of Kurdistan. Similarly, on October 1, 2017, the Catalan voted in an independence referendum in favor of separating...
Learn about how it all works at least. The facts provided in the link are enough so that I don't need to voice an opinion.
Other than to say that Texas is further away from secession now than its ever been.