Yes!
Lets do it

Yes! But I don't think it's a good example. First, the Magna Carta is a peculiar example of concessions being forced out of a King by barons with a knife to his throat, so it isn't really the same thing as a constitution being decided on democratically. It's not a "public" "choice" at all so Buchanan's theory wouldn't be expected to describe it. It is quite clearly one group locking in its momentary political advantage.

More importantly, it isn't actually a constitution; it's almost entirely a bill of rights. From behind your own experimental veil of ignorance I know you may not want to peek and see whether it fits before making a prediction, but I don't think it is appropriate for this experiment, much as I love it. Why not look at a modern democratically (or semi-democratically) selected constitution of a different country? There are plenty that were drafted as recently as the past few decades and about which we have far more information.

The Magna Carta really supports your view. It is explicitly about locking in political privileges, and those are listed. For more amusement you can find the same in the EU constitution. The US constitution has a lot less of that than most I have seen.

The "Veil of Ignorance" view is probably partially correct for constitutions, but I have to agree with you that it can't be fully correct.

I'm in. In your lecture notes that you link to (excellent notes, btw), what does SIVH mean?

David, SIVH="Self-Interested Voter Hypothesis." See this lecture for more.

I believe SIVH is self-interested voter hypothesis

I was too slow

Thanks, Bryan and Scott.
As I was driving along, I said, "Of course, given Bryan's work, it must be self-interested voter hypothesis." I teach your point in the two hours I spend on public choice. Just forgot the name.

Let us gather on Runnymede.