In the Wall Street Journal, Jay Lefkowitz and Michael Shumsky defend the US v. Arizona result as a fair application of preemption—and ask whether the Obama administration will be as solicitous of the doctrine when it comes to upsetting the trial lawyers in drug litigation.

There's a difference, however, between Arizona and Buckman: there exists a federal statute requiring DHS to assist local law enforcement. There is no similar FDA obligation. The argument for Buckman preemption is stronger in the FDA context.