On June 22, 2023, the U.S. Supreme Court issued Pugin v. Garland, 143 S. Ct. 1833 (2023), an immigration decision addressing the generic definition of the obstruction of justice aggravated felony ground at 8 U.S.C. § 1101(a)(43)(S). The Court held that a conviction may be an offense “relating to obstruction of justice,” even if it does not require that an investigation or proceeding be pending or reasonably foreseeable. In doing so, Pugin reversed favorable case law in the Ninth Circuit, Valenzuela Gallardo v. Barr, 968 F.3d 1053 (9th Cir. 2020). The decision may result in the Department of Homeland Security (DHS) charging a broader range of offenses under the obstruction of justice aggravated felony ground. This practice alert reviews the generic definition of obstruction of justice prior to Pugin (Section I); the facts, holding, and reasoning in Pugin (Section II); and the key implications of the decision for practitioners (Section III).