One of the many disputes that led to the Civil War concerned federalism. There was a fundamental disagreement regarding how much power the federal government should have over the states and their rights as a sovereign entity. Many Southerners felt that state governments alone had the right to make important decisions (like whether slavery should be legal).
When slavery and tariffs became controversial states' rights issues, John C. Calhoun (a senator from South Carolina and eventual Vice-President) claimed that states had the right to nullify, or reject, a federal law. Advocates of states’ rights, like Calhoun, believed that the individual state governments had power over the federal government because the states had ratified the Constitution to create the federal government in the first place.
Most Southern states declared independence in an effort to secede from the Union because they felt that secession was the only way to protect their rights. But Abraham Lincoln and many Northerners held that the Union could not be dissolved. When President Lincoln objected to the attempted succession of many southern states, the Civil War began. With the South's defeat in 1865, national supremacy was once again affirmed.
The Union victory solidified the federal government’s power over the states and ended the debate over states’ rights in that period. Several changes were made to the Constitution that granted more power to the federal government.
The addition of the Fourteenth Amendment, which was ratified a few years after the Civil War in 1868, includes three key clauses, which limit state power and protect the basic rights of citizens. The three clauses are as follows:
1. The privileges and immunities clause declares that no state can deny any citizen the privileges and immunities of American citizenship.
2. The due process clause limits states’ abilities to deprive citizens of their legal rights.
3. The equal protection clause declares that all people get the equal protection of the laws.
This was a large shift in history, as the federal government took a more centralized role in the realm of individual rights. Prior to this time, states were more like tiny countries and were allowed to treat their citizens as they saw fit. The Civil War brought about the notion that anyone living in any state in the United States was granted certain protection, and that would be enforced by a strong centralized power that reigned supreme over states.
The federal government enforced new laws and began Reconstruction, which was an era when the federal government attempted to transform the southern states’ economies, which were dependent upon slavery. Congress amended the Constitution for the first time in decades. These amendments included the thirteenth (abolishment of slavery), fourteenth (described earlier), and fifteenth amendment (the right to vote despite race).
As stated, this new idea that the federal government was responsible for the protection of a citizen's individual rights dramatically changed the dynamic of the American government system. It led to the growing ideology that the federal government was in place to protect each and every citizen from state governments that may be denying certain inalienable rights because of some arbitrary characteristic like race, sex, and so on.