One of the tools the Department of Justice has used in the War on Terror is 18 U.S.C. § 2339B, which makes it a crime to donate material support knowingly to Foreign Terrorist Organizations. The statute has raised several constitutional questions, including whether it violates the Due Process Clause’s principle of “personal guilt”—a principle the Supreme Court announced nearly fifty years ago in Scales v. United States—because it does not require the government to prove a defendant’s specific intent. Thus far, there has been little analysis of this due process question; this Note aims to help fill that gap. First, this Note argues that although issues of personal guilt are similar to those found in First Amendment expressive association cases, the due process test is an independent analysis. Yet, cleaving the due process and First Amendment questions leaves a problem: how to give content to the Scales principle of personal guilt. Second, this Note argues that courts should look to extant substantive criminal law—in particular, the doctrines of conspiracy and complicity—for analogies that shed light on just how Scales bears on § 2339B.