More or less, yes. To know 'the law' in common law, it's not enough to know (and understand) statutes (legislation). You must also know relevant 'case law' (published appellate opinions). It's quite complicated, and more than a little subjective.
And the great danger, as we're seeing right now, is that sufficiently pig-headed or corrupt appellate courts might interpret the law as they please, and concoct plausible explanations. And then that becomes 'the law'. It's just too dangerous.