On July 13, 2026, the attorneys general of California, Connecticut, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, New York, Washington, and the District of Columbia filed an amicus brief in support of Colorado in the en banc proceedings before the U.S. Court of Appeals for the Tenth Circuit in National Association of Industrial Bankers, et al. v. Weiser. These “Blue State” amici urge the court to reverse the district court’s preliminary injunction and uphold Colorado’s interpretation of Section 525 of the Depository Institutions Deregulation and Monetary Control Act of 1980 (DIDMCA). Previously, 21 “Red States” filed an amicus brief supporting the plaintiff trade associations that are challenging the Colorado opt-out statute.

The states explain that they have a substantial interest in the appeal because, in their view, the plaintiffs’ interpretation of DIDMCA would effectively eliminate the authority Congress reserved to states to opt out of DIDMCA’s interest-rate exportation provisions and restore their own usury laws. They contend that the plaintiffs’ reading “would nullify” states’ ability to protect their residents from predatory lending.

The Blue States Frame the Case as One About State Sovereignty

Unlike several of the amicus briefs filed on behalf of the banking industry, which emphasize competitive parity between state and national banks and the importance of interstate lending, the Blue State amici present the case primarily as one involving state sovereignty.

The brief begins by arguing that states have historically possessed the sovereign authority to protect their residents through usury laws, regardless of where a lender is located. According to the amici, courts have long recognized that states may apply their consumer protection laws to transactions involving their residents, even when the seller or lender operates from another jurisdiction. The brief points to numerous decisions, including Quik Payday v. Stork, 439 F.3d 1302 (10^th Cir. 2008); Otoe Missouria Tribe v. New York State Department of Financial Services, 769 F.3d 105 (2d Cir. 2014); Consumer Financial Protection Bureau v. CashCall, Inc., 35 F.4th 734 (9th Cir. 2022) ; and TitleMax of Delaware, Inc. v. Weissmann, 24 F.4th 230 (3d Cir. 2022), that applied a state’s lending laws based on the borrower’s location.

The amici argue that this historical backdrop is critical because Congress enacted DIDMCA against a legal landscape in which states generally regulated loans made to their own residents.

The Blue States Assert That DIDMCA Created a Different Balance Than the National Bank Act

The brief next contrasts the National Bank Act (NBA) with DIDMCA.

According to the amici, Marquette National Bank v. First of Omaha Service Corp., 439 U.S. 299 (1978) recognized that the NBA permits national banks to export the interest rates authorized by their home states. Congress subsequently extended comparable authority to state-chartered banks through Section 521 of DIDMCA. Unlike the NBA, however, DIDMCA also includes Section 525, which permits states to opt out of that preemption.

The states argue that this distinction reflects a deliberate congressional compromise. They contend that Congress sought to place state-chartered banks on more equal footing with national banks while simultaneously preserving state authority by allowing states to restore their own usury laws through the opt-out mechanism. The amici rely extensively on legislative history, including testimony before Congress and statements from banking regulators and legislators, all of which they contend demonstrate that Congress intended states to retain meaningful authority to reestablish their usury limits if they chose to do so.

The brief also notes that Iowa and Puerto Rico have long exercised their statutory opt-out rights and observes that Colorado is the most recent state to do so in response to concerns over bank-fintech partnerships that facilitate high-interest lending. The amici further note that several other states have considered similar legislation in recent years.

The Blue States Argue That Plaintiffs’ Interpretation Would Defeat Congress’s Compromise

The heart of the brief argues that the plaintiffs’ interpretation of Section 525 would effectively eliminate the value of the opt-out provision.

According to the amici, Congress did not intend states to be able only to prevent their own state-chartered banks from exporting interest rates while leaving out-of-state state banks free to charge higher rates to the state’s residents. Such an interpretation, they argue, would invert the very purpose of usury laws, which exist to protect resident borrowers rather than regulate lending by home-state institutions to borrowers elsewhere.

The states also emphasize that Congress deliberately used different language in Sections 521 and 525. Whereas Section 521 focuses on the state “where the bank is located,” Section 525 refers instead to “loans made in” the opt-out state. The amici argue that courts must give independent meaning to those different statutory phrases. In their view, a loan is “made” at least in part where the borrower enters into the loan agreement, receives the funds, and incurs the debt.

The brief further rejects arguments that Colorado’s interpretation would create unmanageable compliance burdens. According to the amici, businesses routinely comply with differing state consumer protection laws, and lenders have historically complied with varying state usury laws long before DIDMCA was enacted.

The Blue States Also Invoke the Presumption Against Preemption

Finally, the amici argue that, even if the en banc court concludes Section 525 is ambiguous, longstanding principles governing federal preemption require that ambiguity be resolved in favor of preserving state authority.

The brief emphasizes that regulation of usury has historically been one of the core police powers reserved to the states. Relying on Supreme Court decisions such as Altria Group, Inc. v. Good, 555 U.S. 70 (2008); CTS Corp. v. Waldburger, 573 U.S. 1 (2014); and Virginia Uranium, Inc. v. Warren, 587 U.S. 761 (2019) the amici contend that where Congress legislates in an area of traditional state authority, courts should not lightly infer federal preemption absent a clear statement from Congress. Because, in the amici’s view, Colorado’s interpretation is at least a plausible reading of the statute, the court should reject the broader preemption urged by the plaintiffs.

Observations

This amicus brief differs from most of the other filings supporting Colorado because it frames the dispute principally as one about federalism rather than banking law. Whereas Colorado’s own supplemental brief focuses heavily on statutory text, and other amici have emphasized the policy benefits of state interest-rate caps, the Blue States’ amicus brief repeatedly returns to a single overarching theme: Congress deliberately preserved state sovereignty by including DIDMCA’s opt-out provision, and that reservation of authority should be interpreted broadly enough to have practical effect.

Eleven states and the District of Columbia have joined the brief, underscoring that the outcome of the Tenth Circuit’s en banc decision will have implications extending well beyond Colorado. If the plaintiffs prevail, the amici argue, states that have exercised, or may someday exercise, their DIDMCA opt-out authority could find that authority substantially diminished. Conversely, if Colorado prevails, other states may be encouraged to revisit whether to opt out of DIDMCA as a means of regulating high-rate lending facilitated through interstate bank-fintech partnerships.