That war forced the seceded states back into the union, but didn't declare that state secession was illegal--that would be a job for the Supreme Court or for Congress to make a clarifying law.
And in the case of Texas--and Virginia(?)--forcibly reuniting the state was illegal. Texas joined the union with an agreement that the state be able to secede and become fully independent again if that was what the state chose.
“And in the case of Texas—and Virginia(?)—forcibly reuniting the state was illegal. Texas joined the union with an agreement that the state be able to secede and become fully independent again if that was what the state chose.”
According to the Tenth amendment, that holds true for every state.
The South was wrong in that war with only one act. They let the hotheads fire on Fort Sumter which ultimately precipated the invasion desired by Lincoln.
The Southern Slave owners were wrong (in my opinion) for having slaves in the first place. But that was an issue for the states themselves to solve.
No she did not. When Texas was admitted to the Union she acquired the same rights and the same protections - and the same restrictions - as every other state. She has no special rights reserved to her alone.
Look at Texas v. White.
Texas joined the union with an agreement that the state be able to secede and become fully independent again if that was what the state chose.
Myth. Read the document yourself: Joint Resolution for Annexing Texas to the United States Approved March 1, 1845