The U.S. Department of Agriculture’s Supplemental Nutrition Assistance Program (SNAP)—formerly, the Food Stamp Program—provides low-income participants with electronic benefits that are used like debit cards to purchase eligible food items in authorized retail food stores. Over the program’s long history, policymakers have implemented numerous changes in program design in response to the political, economic, and budgetary environment. Even though SNAP is a mature program, a number of issues continue to arise, such as whether to change SNAP to a block grant program, what types of foods program benefits should cover, and whether benefit amounts and program accessibility are adequate. This report examines the evolution of SNAP—highlighting the effects on the program of major policy and economic changes—to shed light on why the program takes its current form. The report also examines several current issues—each of which has been raised multiple times in the past—and identifies tradeoffs between various program design features. By providing historical and analytical perspective on major program design issues, this report looks ahead by looking back.