War has affected American society and culture in many ways. In particular the Civil War (1861–1865) was a conflict over a theory of government as well as a war to end slavery. The South ascribed to the theory that the states were supreme and that the national or federal government was created by the states. Under this theory the United States was more like a compact formed by independent countries, in which states retained the right to decide what national laws applied to them and even the right to withdraw from the compact. The victory of the North in the Civil War rejected, but has not removed, that theory from the mainstream of American society.

In 1787, during the debates over the Constitution, the issue of state's rights came to center stage. Though almost all agreed that the national government...