No, Texas has the right to secede per the Texas State Constitution. According to the Supreme Court of the United States it does not. But face it, if Texans decide to leave they will be looking to their own constitution first and not that of the United States.
And to those who think the federal tanks would roll into Texas to settle the issue one must consider that two things. First, that it's Texas citizens who make up about 20% of the total military strength of the US Armed Forces. And second, that the home of the largest formation of Heavy Armored units is ..... Fort Hood Texas, the III Armored Corps. So who is it that has the tanks to start with?
Yes and all that belongs to the US Army, not the Texas National Guard, you guys wouldn't be defending your boarders as the Army is already in there. Texas would absolutely not win any type of civil war. "20%!!! blah blah" well yeah that leaves the other 80% for you to deal with. 80 > 20.
But whatever, Texas and California aren't going anywhere. And any chance of that is more likely in congress and court rooms than any type of fighting.