Appeal from the United States District Court for the Eastern District of New York No. 19-cv-6387, Ann M. Donnelly, Judge. Ramon K. Jusino, formerly a tenured theology teacher at a Roman Catholic high school in Staten Island, appeals from the dismissal of his complaint against his labor union, the Federation of Catholic Teachers (the “FCT”), for allegedly breaching its duty of fair representation under the National Labor Relations Act (the “NLRA”) as amended by the Labor Management Relations Act (the “LMRA”), and for assorted violations under the New York State and New York City human rights laws. The district court (Donnelly, J.) dismissed Jusino’s duty-of-fair-representation claim with prejudice for lack of subject-matter jurisdiction, pursuant to Federal Rule of Civil Procedure 12(b)(1), reasoning that the NLRA and LMRA are inapplicable to disputes between parochial-school teachers and their labor unions under NLRB v. Catholic Bishop of Chicago, 440 U.S. 490 (1979). The district court then declined to exercise supplemental jurisdiction over Jusino’s state — and municipal-law claims, which it dismissed without prejudice. We conclude, as a matter of first impression, that Catholic Bishop does preclude Jusino’s duty-of-fair-representation claim, but that dismissal was warranted under Rule 12(b)(6) for failure to state a claim on which relief could be granted, rather than for lack of federal subject-matter jurisdiction under Rule 12(b)(1). We also conclude that Jusino has abandoned any challenge to the dismissal of his state — and municipal-law claims. As a result, we AFFIRM the judgment of the district court. Judge Calabresi concurs in a separate opinion. AFFIRMED. RICHARD SULLIVAN, C.J. Ramon K. Jusino was suspended from his position as a tenured theology teacher at Notre Dame Academy, a Roman Catholic high school in Staten Island, after giving a controversial lecture on racism and human sin. Jusino’s labor union, the Federation of Catholic Teachers (the “FCT”), initiated a formal grievance on his behalf and commenced arbitration proceedings against Notre Dame, asserting that his suspension constituted a breach of the applicable collective bargaining agreement. But when Jusino asked the FCT to raise additional allegations of discrimination and retaliation at the arbitration, it refused. Jusino then sued the FCT for this alleged breach of its duty of fair representation under the National Labor Relations Act of 1935 (the “NLRA”), 29 U.S.C. §151 et seq., as amended in relevant part by section 301 of the Taft-Hartley Act of 1947 (commonly known as the Labor Management Relations Act, or the “LMRA”), id. §185. He also sued the union under the New York State Human Rights Law (the “NYSHRL”), N.Y. Exec. Law §290 et seq., and the New York City Human Rights Law (the “NYCHRL”), N.Y.C. Admin. Code §8-101 et seq. Relying on the Supreme Court’s holding in NLRB v. Catholic Bishop of Chicago, 440 U.S. 490 (1979), the district court (Donnelly, J.) dismissed the duty-of-fair-representation claim with prejudice for lack of subject-matter jurisdiction, pursuant to Federal Rule of Civil Procedure 12(b)(1), reasoning that the NLRA and LMRA are inapplicable to disputes between parochial-school teachers and their labor unions. The district court then declined to exercise supplemental jurisdiction over the state — and municipal-law claims, which it dismissed without prejudice. On appeal, we are tasked with deciding four questions: first, whether the district court properly concluded that Catholic Bishop precludes a parochial-school teacher’s duty-of-fair-representation claim against his labor union under the NLRA as amended by the LMRA; second, if so, whether the inapplicability of the NLRA and LMRA is jurisdictional in character — such that Jusino’s duty-of-fair-representation claim was properly dismissed under Rule 12(b)(1) as opposed to Rule 12(b)(6); third, if the latter, whether the appropriate appellate remedy is to vacate the dismissal order with instructions to re-dismiss or simply to affirm such order on different grounds; and fourth, whether the district court properly declined to exercise supplemental jurisdiction over Jusino’s state — and municipal-law claims. We conclude, as a matter of first impression, that Catholic Bishop does preclude Jusino’s duty-of-fair-representation claim here, but that its application requires dismissal under Rule 12(b)(6) for failure to state a claim on which relief could be granted, rather than for lack of federal subject-matter jurisdiction under Rule 12(b)(1). We also conclude, as compelled by our precedents, that affirmance is the proper appellate remedy in this scenario. Finally, we find that Jusino has abandoned any challenge to the dismissal of his state — and municipal-law claims. As a result, we AFFIRM the judgment of the district court. I. BACKGROUND A. Facts The FCT is the labor union that serves as the exclusive bargaining agent and labor representative for lay teachers in Catholic schools in New York City and several surrounding counties. Until August of 2018, Jusino was a tenured theology teacher at Notre Dame Academy of Staten Island (“Notre Dame”), a Catholic all-girls high school located within the Roman Catholic Archdiocese of New York. The terms of Jusino’s employment at Notre Dame were governed from September 1, 2014 through August 31, 2018 by a collective bargaining agreement (the “CBA”) between the FCT and Notre Dame (through its membership in the Association of Catholic Schools). The CBA provided that tenured teachers, such as Jusino, could only be terminated for just cause. It also provided that “the Employer…shall [not] discriminate against teachers on the basis of…race, color, national origin[,] or sex” and explicitly incorporated into “the terms of employment of teachers in the member schools…all…statutes governing non-discrimination in employment…and all other applicable legislation, governmental regulations[,] or judicial determinations [thereupon].” J. App’x at 9
14-15. In May of 2018, Jusino taught a theology class on the sinfulness of racism, the centerpiece of which was a lecture titled “Racism as Sin.” While the record below is somewhat muddy,1 it appears that the “fallout” of the lecture entailed heated arguments between Jusino and Notre Dame students, parents, and administrators, Dist. Ct. Doc. No. 14 at 2-3, and ultimately resulted in Notre Dame’s “suspend[ing]” Jusino “ without pay” and “with intent to discharge” as of August 2018, J. App’x at 9, 11
