Final answer:
Texas' secession from the Union means it declared its departure from the United States, motivated by states' rights and support for slavery. The concept remains in contemporary discourse through the Texas Secede! organization advocating for Texas' independence.
Step-by-step explanation:
When we say that Texas seceded from the Union, we are referring to the event during the American Civil War when Texas declared its withdrawal from the United States. This action occurred shortly after South Carolina's secession and the subsequent secession of Mississippi, Florida, Alabama, Georgia, and Louisiana. The secessionist movement in Texas was motivated by the state's desire to uphold states' rights and the institution of slavery.
The idea of secession has persisted in some forms, as exemplified by the Texas Secede! organization. Formed as a modern political and social movement, the organization advocates for Texas to secede again and become an independent republic. Supporters reference both Texas and national history, emphasizing a return to individualistic roots and a challenge to what they consider governmental overreach.