US v. Brooks: Brooks and several codefendants, including Mathis, were charged with several drug counts, including conspiracy to distribute more than 500 grams of cocaine and 50 grams of crack. On appeal, Mathis and another codefendant argued that their convictions violated US v. Collins, 415 F.3d 304 (4th Cir. 2005), which required the jury to determine the amount of drugs attributable to each member of a conspiracy before a mandatory minimum could be triggered.
Proceeding only on Mathis's claim (because the other codefendant admitted at oral argument that he was responsible for more than 50 grams of crack), the Fourth Circuit concluded that Collins had been violated and returned Mathis's case to the district court. Of particular importance, the court rejected the Government's argument that Booker effectively overruled Collins, noting that Collins dealt with mandatory statutory sentencing ranges, not advisory Guideline ranges. The court then quickly rejected challenges by other codefendants to their convictions and sentences. Judge Niemeyer dissented from the Collins holding, arguing that the majority's position was incompatible with that case as well as Booker.