Answer: Article I, Section 10 - Ex post facto clause
Sentencing Jones to 20 years violates the article I, section 10 or the Ex Post Facto Clause. This law retroactively changes the legal status, rules of evidence or consequences of actions that were committed before the enactment of the law. Moreover, in criminal law, it may change the punishment prescribed for a crime, as by adding new penalties or extending sentences and this was the case of Jones, which was prohibited by the U.S. Constitution.