Academic freedom
Academic freedom is a contested issue and, therefore, has limitations in practice. In the United States, for example, according to the widely recognized "1940 Statement on Academic Freedom and Tenure" of the American Association of University Professors, teachers should be careful to avoid controversial matters that are unrelated to the subject discussed. When they speak or write in public, they are free to express their opinions without fear from institutional censorship or discipline, but they should show restraint and clearly indicate that they are not speaking for their institution. Academic tenure protects academic freedom by ensuring that teachers can be fired only for causes such as gross professional incompetence or behavior that evokes condemnation from the academic community itself.