Sadly for Texans, even though the do live in a great and special state, it is not that special. The Texas Revolution was a combined effort by those who supported the reform of the Mexican government and those who favored union with the United States. After the revolution; however, politicians such as President Martin Van Buren opposed annexation due to fears of war with Mexico and knowing Texas would upset the slave state/free state balance. Finally, in 1845 the State of Texas was established under the Joint Resolution for Annexing Texas to the United States and Ordinance of Annexation. The resolution allowed Texas to split into four additional states. There is no right to secession mentioned; the claim that the Texas is the only state allowed to fly their flag at the same level as the United States flag is a myth. Any state can do that.
Finally, legal scholars will point to the Supreme Court case of Texas v. White to show secession is illegal and the southern states secession to form the Confederate State of America was therefore invalid. Catholicgauze, on the other hand, likes to state Southern States v. Lincoln to prove Governor Perry's claim is wrong.