The United States are vs the United States is

Residents of the United States prior to the civil war said "The United States are" instead of "The United States is" because they viewed the United States as individual states working together instead of one nation as a whole. Before the Civil War, the nation was divided into the southern states and northern states in terms of political and cultural views. This caused the civil war to happen. Once the civil war ended, people had started to recognize that the United States is a nation and not just states working together. This is because the result of the civil war brought people together.