Well, I am not a lawyer so I don't know if that can really happen, but you are supposed to be judged by the law that applied to you when you committed the crime, not any different scenario that could be applied to your case in the future (nulla poena sine lege, non-retroactivity of criminal law).

Consider, for example, something that didn't use to be a crime. For example, buying alcoholic drinks. If now they ban alcohol, they cannot start prosecuting people who bought alcohol when it was legal. Even if they announce they will ban buying alcohol, they cannot wait for the law to come into effect to start prosecuting people who bought it while the law was being written and knew it was going to be banned, because it was not banned yet when they bought it. This is not the same case, but it's similar.

What matters is the law that applied to you when you committed the crime, not when you are being judged.

But, as said, I'm not a lawyer.