Courts have long held that, when a criminal law is too vague for a reasonable person to understand, it cannot be enforced. Enforcing it would violate our basic due process protections. The U.S. Supreme Court has just applied the same standard to the Immigration and Nationality Act's definition of a "crime of violence."
Under the INA, non-citizen immigrants who commit crimes of violence and certain other aggravated felonies are subject to mandatory removal and deportation. For the purposes of this case, the INA defines a crime of violence using an existing federal law, 18 U.S.C. §16(b), which defines crimes of violence for a variety of other laws.