American decline is when the United States becomes less powerful and influential than it used to be. This means that other countries become more powerful and the U.S. becomes less noticed or respected around the world. This can be caused by different things, such as a decrease in the economy, not being able to compete with other countries, and not having enough resources. It can also be caused by other countries becoming more powerful and taking the lead in different areas like technological advancement, financial stability, and military influence.