Two innovative federal crimes, 18 U.S.C. §2339A and §2339B, have been frequently charged in prosecutions since September 11, 2001, becoming key elements in the government’s anti-terrorism efforts. Section 2339A makes it a federal crime knowingly to provide material support or resources in preparation for or in carrying out specified crimes of terrorism. Section 2339B prohibits knowingly providing material support to a foreign terrorist organization. These statutes bear some resemblance to criminal liability for complicity, but they are being used like a new kind of conspiracy charge, the familiar “prosecutor’s darling.” Unlike conspiracy, they are framed with a mens rea of knowledge rather than of purpose, and because they are substantive offenses, they can be combined with traditional conspiracy charges. These provisions can be used to impose punishment for conduct remote from the commission of criminal harms, often conduct involving minimal and outwardly non-criminal acts.