I do not believe Texas has ever actually seceded........Tejas was part of Mexico, then they fought for their Independence, Remember the Alamo! After their victory, they established the Republic of Texas. The United States of America came calling to kinda 'bully" them into joining them.
In a moment of COMPLETE IDIOCRACY, they agreed. For some years, within the States Constitution was language giving Texas the right to secede should they choose to do so. The US Congress eventually forced them to delete said language from their State Constitution. Again, for whatever reason, they agreed............sigh.....
And, I assure you, these decisions have been regretted ever since.
Now, IF I remember my Texas State History correctly, this is how we came to rue the day we gave up our Independence.