The debate over whether states can secede from the United States was officially put to an end by the Civil War. During his first Inaugural Address, President Abraham Lincoln declared that “no state, upon its own mere notion, can lawfully get out of the Union…in view of the Constitution and the laws, the Union is unbroken”.
After the war, the Supreme Court endorsed Lincoln’s view on the constitutionality of secession. In 1868 Texas was a party to a case before the Court, Texas v. White, where the Court ruled that “when Texas became one of the United States, she entered into an indissoluble relation.” The Court put to rest any 10th amendment claims that states retain the right to leave the Union as they please, as Chief Justice Salmon Chase wrote that the Constitution, “in all its provisions, looks to an indestructible Union.”
