In 2010, Congress passed the Fair Sentencing Act and there has been a lot of litigation to determine whether or not it is retroactive. In fact, in US v. Abney (2016) the US Court of Appeals in D.C. Circuit held that counsel is not obligated to predict the outcome of a proposed amendment to the sentencing guidelines, but it is counsel’s duty to seek a continuance until the amendment passed because one court may have different interpretations and not all interpretations will be beneficial to the client.
Thus, defense counsel must be apprised of not only laws that have passed, but pending laws that may impact their clients.