Even though Texans will shake their fists and declare, “Oh yes we can!” In a word? No. In fact in three words, Texas vs White.

In Texas v. White,  (1869) the United States Supreme Court held in a 5–3 decision that Texas, and all the southern states, had remained a state of the United States ever since it first joined the Union, despite its joining the Confederate States of America and its being under military rule at the time of the decision in the case because, in the court’s opinion, the Constitution of the United States did not permit states to secede from the United States, and that the ordinances of secession, and all the acts of the legislatures within seceding states intended to give effect to such ordinances, were “absolutely null”.

Case closed. Texas cannot legally secede from the United States.