Final answer:
States cannot secede from the United States legally, as established by historical events such as the Civil War and Supreme Court rulings like Texas v. White in 1869. Secession movements, although they exist, have no legal basis and are more a political expression.
Step-by-step explanation:
The legal and historical consensus is that states cannot secede from the United States. When South Carolina and several other states attempted to secede leading to the Civil War, their actions were deemed illegitimate and resulted in conflict.
The question was largely settled after the Civil War, and subsequent Supreme Court decisions have further reinforced the idea that the Union is perpetual and indivisible.
For example, in the Supreme Court case Texas v. White in 1869, it was held that states do not have the right to unilaterally secede.
Despite historical instances and ongoing discussions about secession, such as the Texas Secede! movement, these have not been legally recognized and remain more of a political statement than a legally actionable path.
The United States is considered a single nation rather than a collection of independent sovereign entities with the legal right to sever their bonds unilaterally.