In United States constitutional law, the doctrine of constitutional avoidance dictates that a federal court should refuse to rule on a constitutional issue if the case can be resolved on a nonconstitutional basis. When a federal court is faced with a choice of ruling on a statutory, regulatory or constitutional basis, the Supreme Court has instructed the lower court to decide the federal constitutional issue only as a last resort: "The Court will not pass upon a constitutional question although properly presented by the record, if there is also present some other ground upon which the case may be disposed of." Ashwander v. Tennessee Valley Auth., 297 U.S. 288, 347 (1936) (Brandeis, J., concurring).
The avoidance doctrine flows from the canon of judicial self-restraint, and is intertwined with the debate over the proper scope of federal judicial review and the allocation of power among the three branches of the federal government and the states. It is also premised on the "delicacy" and "finality" of judicial review of legislation for constitutionality, concerns regarding the credibility of the federal courts, and the "paramount importance of constitutional adjudication in our system." These elements demonstrate a significant overlap between the avoidance doctrine and other jurisdictional or justiciability barriers. The avoidance doctrine reflects such other justiciability doctrines as standing and ripeness, and permeates jurisdictional doctrines such as Pullman abstention and the adequate and independent state ground doctrine.
The avoidance of unnecessary constitutional decisions has been urged as early as 1833 by Chief Justice John Marshall in Ex parte Randolph, 20 F. Cas. 242, 254 (C.C.D. Va. 1833) (No. 11,558).
Although Brandeis's concurring opinion in Ashwander is the primary cite for the modern formulation of the avoidance doctrine, Chief Justice Marshall had cautioned previously that no questions of "greater delicacy" can be presented to the federal judiciary than those involving a constitutional challenge to a legislative act. He instructed that if such questions "become indispensably necessary to the case," they must be decided, but "if the case may be determined on other points, a just respect for the legislature requires, that the obligation of its laws should not be unnecessarily and wantonly assailed." In Ex parte Randolph, the Chief Justice, while riding circuit, considered a challenge to a congressional act which provided that Treasury agents could issue warrants for military officers charged with disbursing public funds who failed to pay and settle their accounts at the Treasury Department. The court concluded that the terms of the act did not apply to an officer temporarily acting as the ship's purser due to the death of the regularly commissioned purser and granted his petition for habeas corpus. Justice Louis D. Brandeis's concurring opinion in Ashwander provides the most significant formulation of the avoidance doctrine, even though the Brandeis formulation had no effect on the outcome of the case because the Justice concurred in the plurality opinion, and the plurality considered and decided the properly presented constitutional issues. In Ashwander, Justice Brandeis identified seven components of the avoidance doctrine.