claimed a lien or a mortgage on the property of the trust when the suit was filed, the complainants may not hale the United States into court under 28 U.S.C. § 2410. Accordingly, we must dismiss this appeal and remand the case to the district court with instructions to dismiss the suit against the United States and to remand the case to the state court for further proceedings consistent with this opinion. Although the parties and the district court did not raise these jurisdictional issues, “federal trial and appellate courts have the duty to examine the basis for their subject matter jurisdiction, doing so on their own motion if necessary.” Torres v. Southern Peru Copper Corp., 113 F.3d 540, 542 (5th Cir.1997); Perez v. Region 20 Educ. Serv. Ctr., 307 F.3d 318, 333 n. 8 (5th Cir.2002) (<HOLDING>). I. Background Turner Hunt Lewis, a resident
holding that sovereign immunity issues may be raised sua sponte as they bear on subject matter jurisdiction holding that a lack of a waiver of sovereign immunity deprives federal courts of subject matter jurisdiction holding that the sovereign immunity defense may be raised for the first time on appeal recognizing federal courts duty to determine matter of its own jurisdiction sua sponte whenever it becomes apparent that jurisdiction may be lacking holding issues related to subject matter jurisdiction may be raised at any time