The Second Circuit has determined that when evaluating the deportability of a respondent based on a drug conviction, the agency must compare the statute of conviction to the Controlled Substances Act (CSA) as it was in effect at the time of the person's conviction.  Thus, even if the CSA is amended after the person's conviction but before his removal proceedings, it is the text of the CSA at the time of the conviction that is applicable.  

The full text of Doe v. Sessions is available here: