¥f public opinion changes and then public policy responds, this is dynamic representation. Public I opinion is the global policy preference of the American electorate. Policy is a diverse set of acts of JL. elected and unelected officials. Two mechanisms of policy responsiveness are (1) elections change the government's political composition, which is then reflected in new policy and (2) policymakers calculate future (mainly electoral) implications of current public views and act accordingly (rational anticipation). We develop multiple indicators of policy activity for the House, Senate, presidency, and Supreme Court, then model policy liberalism as a joint function of the two mechanisms. For each institution separately, and also in a global analysis of "government as a whole," we find that policy responds dynamically to public opinion change. This responsiveness varies by institution, both in level and in mechanism, as would be expected from constitutional design.