Civil Procedure

SMJ is non-waivable. A lack of SMJ may be raised at any time by any party, by the court sua sponte, and even for the first time on appeal; if SMJ is lacking the court must dismiss.

It must dismiss the action; a federal court cannot adjudicate a case over which it lacks SMJ, regardless of how far the litigation has progressed.

Under 28 U.S.C. §1331, district courts have jurisdiction over claims 'arising under' the Constitution, laws, or treaties of the United States.

The federal issue must appear on the face of the plaintiff's own well-pleaded complaint as part of the plaintiff's claim, not in a defense or in an anticipated defense.

No. Neither a federal defense (Mottley) nor a federal counterclaim (Holmes Group) satisfies the well-pleaded complaint rule; the federal issue must be in the plaintiff's affirmative claim.