In October 2019, Attorney General Barr issued Matter of Thomas & Matter of Thompson, altering the standard for when immigration law will recognize a criminal sentencing modification. Since then, government attorneys from ICE and adjudicators from DHS and DOJ have misused and exploited the decision to incorrectly impose immigration consequences on vacated and modified past convictions and sentences. Immigrant rights advocates have pushed back by attacking this decision in the federal courts. In this amicus brief submitted to the Seventh Circuit Court of Appeals, immigration law experts directly challenge the AG's decision, arguing it is incorrect as a matter of law, is not entitled to any level of deference, and if permitted to stand cannot be applied retroactively. These arguments build on a growing body of case law refusing to offer deference to the DOJ on interpretation of immigration provisions that have both civil and criminal application. E.g., Valenzuela Gallardo v. Barr, --- F.3d ---, 2020 WL 4519085 (9th Cir. Aug. 6, 2020). Advocates challenging Thomas/Thompson in agency and court proceedings can use the arguments in this brief to attack the case on the merits and to resist its retroactive application.