This commentary introduces a special section of AJPH on the Supplemental Nutrition Assistance Program (SNAP), the US government's largest antihunger program and third-largest antipoverty program. SNAP demonstrably lifts adults, children, and families out of poverty, thereby constituting a vital component of this nation's public health safety net.Despite its well-documented benefits, SNAP is under political and budgetary siege, mainly from congressional representatives and lobbying groups opposed to a federal role in welfare. In part, SNAP is protected from total annihilation by its unusual authorizing legislation-the Farm Bill.This commentary provides a brief overview of the political history of SNAP and its Farm Bill location as background to the deeper analyses provided in this series of articles.