What replaced feelings of sectionalism in the early 1800s?

In the early 1800s, feelings of sectionalism were increasingly replaced by a sense of nationalism as the United States expanded and developed a more unified national identity. This shift was driven by economic growth, westward expansion, and cultural movements that emphasized shared American values and ideals. However, underlying tensions remained, especially regarding slavery and states' rights, which would eventually resurface and contribute to the Civil War. Despite the rise of nationalism, regional differences continued to influence American politics and society.