The U.S. Constitution is currently the subject of a heated political debate. Tea Party activists have invoked the Constitution as the foundation of their conservative political philosophy. These activists are engaged in “popular originalism,” using popular constitutionalism—constitutional interpretation outside of the courts—to invoke originalism as interpretive method. The Tea Party movement thus provides an excellent heuristic to explore the relationship between originalism and popular constitutionalism, two prominent trends in constitutional theory. Both originalists and popular constitutionalists study legal history to illuminate constitutional meaning, but the two schools of thought draw diverging lessons from that history. Originalists look to history to determine the fixed “original” meaning of the Constitution, which they hold to be binding on contemporary interpreters, regardless of subsequent historical or political developments. Popular constitutionalists study the way in which constitutional interpretation has been influenced by historical developments and explore the use of constitutional theory to bolster constitutional arguments.