U.S. judges have been hard-wired against rendering “advisory opinions” since 1793, when the first chief justice, John Jay, declined to answer George Washington’s legal questions about the status of a British ship that had been captured by the French and brought to an American port. To answer the president’s questions, Jay wrote, would violate “the lines of separation drawn by the Constitution between the three departments of the government.” Jay’s letter referred to Article II, Section 2 of the Constitution, which provides that the president “may require the opinion, in writing, of the principal officer in each of the executive departments, upon any subject relating to the duties of their respective offices” — a provision, Jay wrote, that “seems to have been purposely as well as expressly united to the executive departments.”

From that letter — itself an advisory opinion — has grown a complex but well-established and understood set of constraints on the federal courts: They are to decide only “cases” or “controversies” that are “justiciable” and “ripe” for decision. Federal courts rule on specific disputes between adversary parties. They do not make or approve policy; that job is reserved to Congress and the executive.