States' Rights

The theory of states' rights is grounded in the Tenth Amendment, which says that powers not specifically granted to the federal government or prohibited to the states are reserved to the states or the people.  Thomas Jefferson and James Madison helped developed the theory when they attacked the 1798 Alien and Sedition Acts in the Virginia and Kentucky Resolutions.    They argued that states should be able to "nullify" federal acts they found unconstitutional. 

Southern states argued the early decades of the 19th century, when they opposed tariffs passed by Congress to protect Northern manufacturing which they said penalized the South.   Southern states also maintained it was their right to secede from the Union.  The result was the Civil War.