Dual federalism is when a national government and a state government operate individually, as was the case for the United States until the Great Depression. Dual federalism naturally limits the power of the national government as it gives states the ability to make their own decisions and question the rulings of the national government.
Throughout the United State's dual federalism period, the national government was responsible for issues dealing with the nation, such as national defense, building the economy and dealing with foreign policy. The states took over everything else including their own state economic regulation, local matters and criminal law.
Dual federalism came to an end in part due to the Civil War. During the Civil War, the Southern states believed that they should be able to make their own decisions about important matters, including slavery. The Northern states, however, did not believe that the states should be given pure authority on such an important matter. They also did not believe that the union of the states should be dissolved based on this disagreement. They felt that there should be a unifying single rule on the issue.
When the Great Depression occurred, people were in shock and in trouble. President Roosevelt created the "New Deal" policies, which intruded upon people's lives in a way that the government had not previously done. From here, the dual federalism government of the United States became a cooperative federalism government.