(emphasis added); accord Fed. R. Civ. P. 12(h)(3) (“If the court determines at any time that it lacks subject-matter jurisdiction, the court must dismiss the action.” (emphasis added)). Anderson does not challenge subject matter jurisdiction; he seeks to defend it. And he waived any arguments in defense of subject matter jurisdiction by failing to raise them below, just as other legal arguments not properly raised in the district court. This court has, on at least two occasions, addressed nearly identical fact patterns, and on both occasions it found that the plaintiffs waived their argument that the defendant consented to subject matter jurisdiction by failing to raise it before the district court. See Martinez v. Tex. Dep’t of Criminal Justice, 300 F.3d 567, 573-75 (5th Cir. 2002) (<HOLDING>); Perez v. Region 20 Educ. Serv. Ctr., 307 F.3d
holding that state did not waive eleventh amendment immunity by removing case to federal court holding that a party in a habeas case waives an argument by failing to raise it before the district court holding that the defendant waived an argument by failing to raise it in his appellants brief holding that state defendant waived eleventh amendment immunity to a federal claim by removing to federal court holding that a plaintiff waived an argument that the defendant voluntarily waived its eleventh amendment immunity by removing the case from state to federal court by failing to raise it before the district court even though an intervening supreme court decision clarified the law in the plaintiffs favor