Explanation: During the US Civil War, the state of Texas was one of the states which attempted to secede in order to preserve slavery.

Despite being a slaveowner himself, Sam Houston, who was pivotal in the Texan revolt against Mexico and Texas’s subsequent acceptance into the USA, still valued the Union more than slavery, and was staunchly against secession. Which, while a low bar, is still a bar that the majority of Texan politicians at the time apparently could not likewise clear.

Texas would later join the rest of the seceding states in getting crushed by the antislavery North and reintegrated into the Union under a military administration for nearly a decade.

"Let me tell you what is coming. After the sacrifice of countless millions of treasure and hundreds of thousands of lives, you may win Southern independence if God be not against you, but I doubt it. I tell you that, while I believe with you in the doctrine of states rights, the North is determined to preserve this Union. They are not a fiery, impulsive people as you are, for they live in colder climates. But when they begin to move in a given direction, they move with the steady momentum and perseverance of a mighty avalanche; and what I fear is, they will overwhelm the South.”

And the one I hadn’t seen before

" Fellow-Citizens,” he wrote, in the name of your rights and liberties, which I believe have been trampled upon, I refuse to take this oath. In the name of the nationality of Texas, which has been betrayed by the Convention, I refuse to take this oath. In the name of the Constitution of Texas, I refuse to take this oath. In the name of my own conscience and manhood, which this Convention would degrade by dragging me before it, to pander to the malice of my enemies, I refuse to take this oath. I deny the power of this Convention to speak for Texas. . . . I protest . . . against all the acts and doings of this convention and I declare them null and void."