Rose J. Spano was suspended and ultimately disbarred from the practice of law in Florida. She brought a suit in federal court alleging, among other things, that the procedures resulting in her suspension and disbarment, and the rules that governed those procedures, deprived her of due process and equal protection. Among those she sued were the Justices of the Florida Supreme Court. The district court granted the Justices’s motion to dismiss Spano’s claims against them for lack of subject matter jurisdiction. Spano appeals that order. 1

We review de novo a district court’s resolution of a motion to dismiss for lack of subject matter jurisdiction. Community State Bank v. Strong, 651 F.3d 1241, 1251 (11th Cir. 2011). But we will not address arguments not made in an appellant’s initial brief. United States v. Curtis, 380 F.3d 1308, 1310 (11th Cir. 2004). Nor will we develop on our own issues that a party mentions only in passing. Lapaix v. U.S. Att’y Gen., 605 F.3d 1138, 1145 (11th Cir. 2010); see also Fed. R.App. P. 28(a)(5), (9).

The district court determined that it lacked subject matter jurisdiction over Spano’s claims against the Justices because they were not “persons” within the meaning of 42 U.S.C. § 1983. Yet Spa-no’s argument in her initial brief consists entirely of direct challenges to the underlying state disciplinary proceedings. Beyond a cursory reference in the first sentence of her brief setting forth the procedural history, Spano nowhere else mentions the district court’s judgment. And she devotes no attention whatsoever to the substance of the district court’s determination that the Justices were not amendable to suit in their official capacities under § 1983. None of the cases Spano cites in her initial brief were brought under § 1983, so they provide no authority for determining whether the district court’s interpretation of the language of that statute to require dismissal of her claims was in error. Instead, Spano frames the issue on appeal as whether “the Florida Supreme Court reversibly erred” in suspending and ultimately disbarring her. That issue is not *952 properly before us and therefore is not a basis for reversal.

Because we conclude that Spano has waived any argument that the district court erred in dismissing her claims against the Justices for lack of subject matter jurisdiction, we affirm the judgment of the district court. Curtis, 380 F.3d at 1310.

AFFIRMED.