Q: Did the terms of Texas's admission to the Union include permission to withdraw if it found statehood not to its liking?
It is said of Texas (and, occasionally, Vermont) that it received a letter or document of permission to withdraw from the Federal Union if it so chose. In the case of Texas, this permission is sometimes said to have been granted at the time of Texas's admission as a state. Other times it is said to have been included in the terms readmitting Texas to the Union after the Civil War.
In fact, Texas received no special terms in its admission to the Union. Once Texas had agreed to join the Union, she never had the legal option of leaving, either before or after the Civil War.
The early years of the United States had seen a great deal of debate over whether states could, in fact, legally withdraw from the Union. During the War of 1812 it was New England that wanted to secede from the rest of the country. Later, it was the Southern states. Secessionists argued that states were sovereign and had the right to withdraw from the Union. Opponents countered that the Constitution created a sovereign union that, once entered into, could never be broken. Eventually, the question was put to the test and settled permanently on the battlefields of the Civil War.
The Presidential Proclamation declaring peace between the United States and Texas after the Civil War, dated August 20, 1866, states very clearly in the following passage that no state had the right to leave the Union (emphasis added in all capitals):
And whereas,
the President of the United States, by further proclamation issued on the second day of April, one thousand eight hundred and sixty-six, did promulgate and declare, that there no longer existed any armed resistance of misguided citizens, or others, to the authority of the United States in any, or in all the States before mentioned, excepting only the State of Texas, and did further promulgate and declare that the laws could be sustained and enforced in the several States before mentioned, except Texas, by the proper civil authorities, State, or Federal, and that the people of the said States, except Texas, are well and loyally disposed, and have conformed or will conform in their legislation to the condition of affairs growing out of the amendment to the Constitution of the United States, prohibiting slavery within the limits and jurisdiction of the United States;
And did further declare in the same proclamation THAT IT IS THE MANIFEST DETERMINATION OF THE AMERICAN PEOPLE THAT NO STATE, OF ITS OWN WILL, HAS A RIGHT OR POWER TO GO OUT OF OR SEPARATE ITSELF FROM, OR BE SEPARATED FROM THE AMERICAN UNION; and that, therefore, each State ought to remain and constitute an integral part of the United States;
On March 30, 1870, Congress passed the Act to admit the State of Texas to Representation in the Congress of the United States. Likewise, this act contains no language that would allow Texas to unilaterally withdraw from the United States.