Does § 106(a) of the Bankruptcy Code abrogate sovereign immunity only for federal causes of action created by § 544(b)? Or does it also waive immunity for underlying state-law claims that provide the "applicable law" required to satisfy the actual-creditor requirement of § 544(b)? This determines whether a trustee can avoid transfers to the United States when such transfers would be barred by sovereign immunity if brought by a private creditor under state law.

• Respondent cannot identify an "actual creditor" who could have voided the transfer under Utah law because sovereign immunity bars any such cause of action against the Government outside of bankruptcy.
• Section 106(a) is a jurisdictional provision that allows courts to hear claims but does not create new substantive rights or modify the elements of § 544(b).
• Sovereign-immunity waivers must be construed narrowly, and any ambiguity should be resolved in favor of the sovereign.

• The phrase "with respect to" in § 106(a)(1) indicates that Congress intended to abrogate immunity for all subjects concerning § 544, including the elements of the cause of action and the meaning of "applicable law."
• If the waiver does not apply to the underlying state-law claim, then § 106(a)'s reference to § 544(b) would be meaningless because no trustee could ever win such a suit against the Government.
• Congress sometimes waives sovereign immunity while simultaneously establishing new substantive rights, as seen in *Department of Agriculture Rural Development Rural Housing Service v. Kirtz*.

• The Court held that § 106(a)'s sovereign-immunity waiver applies only to the § 544(b) claim itself and not to state-law claims nested within that federal claim.
• Sovereign immunity is "jurisdictional in nature" (*FDIC v. Meyer*) and waivers function as "prerequisite[s] for jurisdiction" rather than creating new substantive rights or altering pre-existing ones (*United States v. Mitchell*).
• The Court relied on § 106(a)(5), which explicitly states that "[n]othing in this section shall create any substantive claim for relief or cause of action not otherwise existing," meaning the waiver cannot modify the "elements" of a § 544(b) claim.
• The Court noted a structural difference between § 544(a), which allows avoidance "whether or not such a creditor exists," and § 544(b), which ties rights to an actual creditor under "applicable law."
• The Court emphasized that § 544(b) is intended to place the trustee "in the shoes of" the creditor, subject to the same limitations—including sovereign immunity—that would apply to a private creditor (*Davis v. Willey*).
• Following *FAA v. Cooper*, the Court applied the rule that ambiguities in sovereign-immunity waivers must be resolved in favor of the sovereign.
• The Court rejected the argument that § 106(a) is rendered meaningless, noting it still allows trustees to prevail under § 544(a) (e.g., avoiding tax liens under 26 U.S.C. § 6323) and against state governments that consent to be sued.
• The Court distinguished *Department of Agriculture Rural Development Rural Housing Service v. Kirtz*, noting that the statute in that case explicitly authorized claims against the Government, unlike the provisions here.