Civil Procedure

No. Subject-matter jurisdiction cannot be conferred by consent, waiver, or estoppel; any party or the court sua sponte may raise its absence at any time, even for the first time on appeal, and the court must dismiss (Rule 12(h)(3)).

The civil action must arise under the Constitution, laws, or treaties of the United States; usually the claim arises under the federal law that creates the cause of action. There is no amount-in-controversy requirement.

Federal-question jurisdiction exists only if the federal issue appears on the face of the plaintiff's properly pleaded claim; federal issues arising only in an anticipated or actual defense, or in a counterclaim, do not confer arising-under jurisdiction (Mottley; Holmes Group).

No. The claim is a state-law contract claim; the anticipated federal defense and plaintiff's constitutional reply do not appear in a well-pleaded complaint, so there is no 1331 jurisdiction, and with no diversity the case must be dismissed.

Under Grable and Gunn v. Minton, when the federal issue is (1) necessarily raised, (2) actually disputed, (3) substantial to the federal system as a whole, and (4) capable of resolution in federal court without disrupting the congressionally approved federal-state balance. This is a special and small category.

Under 28 U.S.C. 1332(a) as construed in Strawbridge v. Curtiss, no plaintiff may be a citizen of the same state as any defendant; one shared citizenship on opposite sides defeats diversity.