The Internal Revenue Service seized real property belonging to petitioner P to satisfy P's federal tax delinquency. Title 26 U.S.C. § 6335 required the IRS to give notice of the seizure. P received actual notice by certified mail before the IRS sold the property to D. P did not exercise its statutory right to redeem the property within 180 days of the sale, §6337(b)(1), and after that period had passed, the Government gave D a quitclaim deed. Five years later, P brought a quiet title action in state court, claiming that D’s record title was invalid because the IRS had failed to notify P of its seizure of the property in the exact manner required by §6335(a), which provides that written notice must be “given by the Secretary to the owner of the property [or] left at his usual place of abode or business.” The statute required personal service, not service by certified mail. D removed the case to Federal Court as presenting a federal question, because the claim of title depended on the interpretation of the notice statute in the federal tax law. The District Court declined to remand the case at P’s behest after finding that the “claim does pose a significant question of federal law,” and ruling that P’s lack of a federal right of action to enforce its claim against D did not bar the exercise of federal jurisdiction. The court granted summary judgment to D, holding that although §6335 by its terms required personal service, substantial compliance with the statute was enough. The Court of Appeals for the Sixth Circuit affirmed. The Supreme Court granted certiorari.