High courts in eleven U.S. states (and a number of countries) provide advi? sory opinions on pending legislation when requested by the executive or legislative branch of the government. To examine the implications of the advisory mechanism for institutional behavior and for policy outcomes, we develop and compare results from two incomplete-information models of judicial-legislative interaction. One game models judicial-legislative inter? action with judicial review, the other models the interaction with an advisory option. We show how the advisory mechanism alters policy outcomes relative to outcomes that would be realized without the advi? sory option. We then identify the conditions under which legislatures request advisory opinions and when they choose to legislate without them. Finally, we consider whether the advi? sory mechanism is a welfare-enhanc? ing or welfare-diminishing institution, and identify conditions that explain why some courts are willing to offer advisory opinions while others refuse to do so. In a well-known episode, President George Washington asked John Jay and the other U.S. Supreme Court justices to advise him on the nation s treaty obligations in light of continuing conflicts among Euro? pean powers. The justices famously declined, citing their concern with vio? lating the separation-of-powers principle.1 Less well known is that many U.S. states rejected the Court's concern and instead created an advisory role for their judiciaries. At one time or another, high courts in nineteen states have given advisory opinions when requested by coordinate branches of government. While some of these courts ultimately turned against their ad? visory role, the high courts of eleven states continue to serve in an advisory capacity today. Opinion over whether the judiciary should serve in an advi? sory role has been divided for centuries. Notable legal commentators, in? cluding Lord Coke, Alexander Hamilton, and Felix Frankfurter, have op? posed judicial advisory opinions. They argue that the abstract setting of advisory proceedings?particularly the absence of detailed factual records as exist in ordinary litigation?undermines a crucial informational compo? nent of judicial decision making. In contrast, other commentators claim that early judicial review is the advantage of advisory opinions. They argue that when legislatures solicit judges' opinions on pending legislation, it re? duces the number of enacted laws that courts will have to strike down in the future. As a result, advisory opinions decrease transaction and reliance costs created by the length of time?often many years?it takes legislation in ordinary litigation to reach high courts for a decision.