[JURIST] The US Supreme Court [official website] ruled [opinion, PDF] in McFadden v. United States [SCOTUSblog materials] on Thursday that in a synthetic drug case, the government must prove that the defendant understood that he was dealing a substance regulated under the Controlled Substances Act or Analogue Act [21 USC §§ 802(32)(A), 813]. The ruling could make it more difficult for prosecutors to convict drug dealers selling chemically modified drugs that are not specifically banned by state and federal drug lists. Justice Clarence Thomas authored the unanimous opinion, where the Court held that prosecutors must prove that the defendant knew the substance was a controlled substance banned under federal law or that he knew the substance was an analog, with a chemical structure substantially similar to the banned drug. Stephen McFadden was convicted in 2013 under the Controlled Substances Analogue Enforcement Act for selling bath salts in Charlottesville, Virginia. The Act punishes those who knowingly or intentionally sell a controlled substance or analogue – a knock-off that has a “substantially similar” chemical structure and has similar effects of a banned substance. The Fourth Circuit [official website] held that it was enough for a jury to find that McFadden intended the bath salts for human consumption. The justices disagreed, and the case has been sent back to the appeals court to determine whether the incorrect jury instruction was harmless. If it is found to be harmless, McFadden’s conviction will stand.

Chief Justice John Roberts wrote a concurring opinion. The court granted certiorari to the case in Janurary and heard oral arguments [JURIST reports] in April.