> since of course what they wrote often didn't clearly articulate what they necessarily meant.

Sure. But what "they necessarily meant by the words they said" is different from "what they would have said if confronted with different facts."

The ownership issue is a good example. Does the word "their ... papers and effects" include third-party data about someone? Third-party data existed in 1789. British people love record-keeping, and the founders were sophisticated people with lawyers, accountants, merchant accounts, etc. If the fourth amendment meant to include third-party information about someone, the founders wouldn't have used the ownership language that they used.

So the real argument is that, if the founders saw how important and sensitive third-party information is today, they would have included it. They wouldn't have used the ownership language they used. That's quite a different argument! It's not just trying to understand what people meant by the words they used. It's trying to reanimate them and ask them questions to scenarios they never contemplated.