Something I've not heard anything about from an authoritative source - in the US, I've noticed laws being written with a preface that makes a political statemen

Something I've not heard anything about from an authoritative source - in the US, I've noticed laws being written with a preface that makes a political statement about what the law is, does, and why, and it is not at all consistent with the rest of it, which defines terms carefully. It seems to be a trick to send a chosen message to the media without having any effect on the court system. So I wonder if that could account for the "unenforceability" of some laws - basically what the law is reported as being, is just a fiction for the public, so the courts don't even engage with it.