The Constitution provides that "no Bill of Attainder or ex post facto Law shall be passed." The Sentencing Reform Act of 1984 provides both that the sentencing guidelines are subject to periodic amendment and that the guidelines and policy statements in effect at the time of sentencing apply. Clearly, Congress did not believe that the ex post facto clause would apply to guideline changes. All circuits that have considered the issue disagree with Congress' determination, finding under the reasoning of Miller v. Florida that guideline amendments that disadvantage offenders and apply to offenses committed prior to the effective date of the amendments violate the ex post facto clause. Effective dates of adverse criminal penalties, be they statutes or guidelines amendments, are amenable to a clear and easy rule, i.e., they apply only to offenses committed on or after their effective date. 13 notes