Quick Study Guide Want to find out what the Federalist Papers were? Not sure what “ex post facto” means? Wonder no more—these and other terms pertaining to the U.S. government can be found within BarCharts’ up-to-date, 3-panel guide. Each term is bolded and defined for easy reference; in addition, all terms are divided into sections addressing particular topics, including the U.S. Constitution, landmark documents and the three branches of government.