Racism refers to the belief that race determines human traits and that racial differences produce inherent superiority. There are a number of small neo-Nazi groups in the United States today that have formed since the 1920s, though their popularity has fluctuated. While the First Amendment allows freedom of speech, including racist and anti-Semitic views, neo-Nazi groups have faced legal issues for certain actions like soliciting murder. The concept of American exceptionalism refers to the belief that the United States differs qualitatively from other developed nations through its values and political institutions.