Complex sentence: The Constitution is silent on the question of whether states have the power to secede from the Union; however, shortly after the Civil War, the U.S. Supreme Court, in "Texas v. White", held that a state cannot unilaterally do so.
Split into simpler sentences: The Constitution is silent on the question of whether states have the power to secede (withdraw from) from the Union. Shortly after the Civil War, the U.S. Supreme Court, in "Texas v. White", held that a state cannot unilaterally do so.