Hamburger and McDonald[s]?

Thanks to Jim for posting Philip Hamburger’s very interesting new paper on the original meaning of the privileges or immunities clause. With the oral argument in McDonald just a few days away, I’m curious what readers who follow these issues closely think of Hamburger’s paper. I’m not enough of a historian to have a firm sense of which side is right, so I’m interested in what our readers think. (Oh, and sorry for the post title: I know, I know, I really shouldn’t have done that, but I just couldn’t help myself.)