TIL Sam Houston, the general who won Texas independence from Mexico, was removed from his post as Governor of Texas after refusing to support the Confederacy during the Civil War

Fort Sumpter was federal property dependent upon its surrounding territory being a member of the union.

There is no magical "take backsie" clause. In 1836, the South Carolina legislature stated:

Also resolved: That the State shall extinguish the claim, if any valid claim there be, of any individuals under the authority of this State, to the land hereby ceded.

That's pretty fucking final. And as Samuel Crawford writes in The Story of Sumter:

“It had been acquired and the jurisdiction yielded by the Legislature of the State in the usual way. There was no special contract between the Federal Government and this Commonwealth, nor any feature which distinguished the legal relations between them from those maintained with the other States of the Union.”

This is why, of course, the CSA attempted to meet with Lincoln to discuss such terms

On January 31, 1861 Govenor Pickens wrote a letter to President Buchanan demanding Fort Sumter, when the Fort had been already been blockaded for weeks.

because they weren't "just magically claiming it",

True, in addition to magic, the South was blockading the Fort and firing on any ships attempting to resupply it.

they were attempting to broker a peace treaty

Nothing says peace like holding someone at gun point and demanding they surrender.

would have included compensation and ensured the territorial integrity of both nations.

You neo-confederates sure can be impressive! South Carolina literally places federal property under siege—having already seized other Federal forts, armories and fortifications—demands Fort Sumter's unequivocal surrender and you're spinning it as a thoughtful attempt to ensure the United States' territorial integrity?

/r/todayilearned Thread Parent Link - en.wikipedia.org