The 1984 Supreme Court decision in Chevron U.S.A. Inc. v. Natural Resources Defense Council, Inc. established the ‘Chevron deference’ doctrine, which required courts to defer to administrative agency interpretations of ambiguous statutes if they were reasonable. This doctrine significantly impacted the financial services sector, making it difficult to challenge the US Department of the Treasury’s actions, such as sanctions and penalties. 

The Fifth Circuit Court of Appeals held that Tornado Cash’s immutable smart contracts are not the “property” of a foreign national or entity, meaning smart contracts cannot be blocked under the International Emergency Economic Powers Act (IEEPA) and OFAC overstepped its authority in sanctioning Tornado Cash.