Baude on Federal Common Law and Choice of State Law After DOMA

Will Baude has a wonderful new piece on what should replace DOMA (as it seems to be expiring) for purposes of deciding which state law ought to control the issue of the validity of a same-sex marriage.  I haven't had a chance to read through all of Will's piece (and it is not in my area -- but Will writes so accessibly that I can pretend that I really understand it as he does), but one of the (many) things that makes it interesting is that Will notes that this issue is just one example of a larger set of issues dealing with "interstitial law":

First, I demonstrate that the second-order conflicts problem for federal question cases should generally be resolved through a federal common law of conflicts. It cannot be resolved by treating federal question cases like diversity cases [Will rejects applying Klaxon to this category of disputes] . . . . Second, I demonstrate that institutional role matters. Congress solves conflicts problems differently than courts do, because it is free to implement a broad range of policy goals through conflicts doctrine, while courts have a more limited role of filling in the gaps between Congress’s choices. Both of these principles apply to all instances of what is here called “interstitial law”—a form of federal law that relies upon state law.