John Ohlendorf on Northwest v. Ginsberg
Michael Ramsey

I thoroughly agree, first, that Ginsberg looks like it came out right, and, second, that the fact that Congress can (and not infrequently does) include an express preemption clause in its legislation pretty well does in the frequent claim that preemption is just too complicated and fact-based for Congress to be effectively involved in the process, and accordingly that preemption must not have much to do with fidelity to Congress.

But regarding whether we can reliably infer from Congress's failure to include an express preemption clause that it meant to foreclose preemption (or foreclose anything but "impossibility" preemption), I had two additional thoughts.  First, Congress can (and not infrequently does) expressly bar preemption, as well, so in any given piece of legislation that contains neither a preemption nor a savings clause, it seems to me that we at best have two contrary implications that cancel each other out.  And second, Abbe Gluck and Lisa Bressman's path-breaking empirical study of Congress's drafting process is a pretty strong piece of evidence that, here as elsewhere, Congress is pretty thoroughly and blissfully ignorant of any stable set of preemption default rules the Court might be trying to craft. (Gluck and Bresseman actually cite preemption doctrine as a success story for Congressional knowledge of statutory interpretation defaults, but if you dig into their data, it turns out that Congress is pretty clueless).