Background - Millard Seldin created the Millard Seldin Children’s Master Trust (MSCM Trust) in 1992; Scott Seldin and siblings were beneficiaries and Theodore Seldin and Stanley Silverman were trustees. The trust required annual accountings and was dissolved in 2002; Scott alleges trustees never provided required accountings. - In February 2010 Scott and Millard entered a Separation Agreement with Appellees to split jointly held assets; the Agreement contained a broad arbitration clause covering disputes about the Agreement or jointly owned property. - Multiple arbitration and state-court actions followed (2011–2013). State courts repeatedly ordered Scott to arbitrate and dismissed his state suits; appeals were later dismissed as moot after arbitration resumed with a new arbitrator. - Scott filed a federal suit in July 2016 seeking an accounting of the MSCM Trust. Appellees moved to dismiss for lack of subject-matter jurisdiction; the district court granted dismissal, citing the arbitration agreement, claim preclusion/collateral estoppel, and Rooker–Feldman. - After briefing for this appeal concluded, the arbitrator issued a Final Award against Scott and Appellees moved in state court to confirm it as a judgment. ### Issues | Issue | Plaintiff's Argument | Defendant's Argument | Held | |---|---:|---|---| | Whether an arbitration agreement deprives federal courts of subject-matter jurisdiction | Scott contended federal court retained jurisdiction to hear his accounting claim despite the arbitration clause | Appellees argued the arbitration agreement divested federal courts of jurisdiction and arbitrator must decide threshold issues | Court: Arbitration agreement alone does not strip federal courts of subject-matter jurisdiction; dismissal under Rule 12(b)(1) was erroneous (City of Benkelman controlling). | | Whether preclusion (res judicata/collateral estoppel) is a jurisdictional bar | Scott implicitly argued preclusion was not jurisdictional and should be addressed on the merits | Appellees argued prior state rulings precluded Scott’s federal claim so court lacked jurisdiction | Court: Preclusion is non-jurisdictional; dismissals based on preclusion should be brought under Rule 12(b)(6) or Rule 56, not 12(b)(1). | | Whether Rooker–Feldman bars Scott’s federal suit challenging state-court orders compelling arbitration | Scott sought to litigate the accounting in federal court (after state-court orders to arbitrate) | Appellees argued Scott was a state-court loser and Rooker–Feldman barred federal review of state-court orders | Court: Rooker–Feldman could bar collateral attack on the state-court order to arbitrate, but the Court need not decide because arbitration has concluded; district court may hear challenges to enforcement of the arbitration award but not relitigate the state order ordering arbitration. | | Whether Intervenors’ denial to intervene affects this appeal | Intervenors sought to join to defend trust beneficiaries’ interests | Appellees opposed intervention | Court: Unnecessary to address denial of intervention given remand and arbitration completion; remand will resolve further proceedings. | ### Key Cases Cited City of Benkelman v. Baseline Eng’g Corp., 867 F.3d 875 (8th Cir. 2017) (arbitration agreement alone does not defeat federal subject-matter jurisdiction; motions to compel are properly raised under Rule 12(b)(6) or Rule 56) Exxon Mobil Corp. v. Saudi Basic Indus. Corp., 544 U.S. 280 (2005) (preclusion is non-jurisdictional; Rooker–Feldman doctrine bars federal review of state-court judgments) In re Athens/Alpha Gas Corp., 715 F.3d 230 (8th Cir. 2013) (res judicata is non-jurisdictional) A.H. ex rel. Hubbard v. Midwest Bus Sales, Inc., 823 F.3d 448 (8th Cir. 2016) (dismissal based on preclusion appropriately addressed under Rule 12(b)(6)) * Smith v. United States, 369 F.2d 49 (8th Cir. 1966) (summary-judgment procedures relevant to preclusion defenses)