Blackstone had quite a bit to say about positive law, and the basis for its validity. When positive law deviates from the principles that give it force, then positive law loses its claim to "moral high ground."
And it only has its practitioners (the judges, mostly) to blame.
Indeed. There’s a pithy treatise on this subject titled “Law. Liberty and Morality” by H.L.A. Hart based on a series of lectures he gave at Stanford some decades ago. If you can find a copy, it’s worth a read.