Civil Procedure

Federal-question cases (28 U.S.C. 1331) and diversity-of-citizenship cases (28 U.S.C. 1332).

No. It can never be waived; it may be raised at any time, even on appeal, and the court must raise it sua sponte.

The federal question must appear on the face of the plaintiff's properly pleaded complaint, not in an anticipated defense or counterclaim.

No. Anticipated federal defenses and federal counterclaims do not satisfy the well-pleaded complaint rule.

Complete diversity of citizenship between all plaintiffs and all defendants, and an amount in controversy exceeding $75,000.

No plaintiff may be a citizen of the same state as any defendant (Strawbridge v. Curtiss).