There's actually two kinds of changes here: changes to the law, and changes to your description of the-law-and-its-changes (metachanges). For example, if you make a mistake in recording a change to the law, you need to fix that (unlike eg a source repo where mistakes in a commit message are forever).

So to make this a git repo, I guess you'd make the snapshots be the law plus markup for all the changes, and the diffs are the metachanges. For each snapshot S, you could generate a git repo whose snapshots are the law and the whose diffs are the changes in the law (as described by S). However, this probably isn't the best way to query S.

Not really. It is arguing for version controlled legislation. So who’s responsible for what portions of literal laws and policy. I hope your "not clone-able" is in jest