John A. Quitman

Union.

There was another gentleman named John Quitman, former governor of Mississippi, who similarly tried to organize an invasion of Cuba to add it as a slavery state to expand southern slavery.

And then there was a man named William Walker, who first invaded Mexico and set up a very short-lived what he called a republic in the Baja California Peninsula and northwestern Mexico before he was driven out.

But he didn't give up.