So let us get this straight: the Obama administration thinks that when it comes to the manufacture of automobiles or pharmaceuticals in interstate commerce, it is critical to permit individual states to impose liability on design or warning-label decisions made on a nationwide basis, even when those standards are inconsistent with federal regulatory standards, but when it comes to individual state legislature decisions about local law enforcement, it is critical to enjoin that action to prevent a "patchwork" of differing state policies. Talk about upside-down federalism.
Update: DOJ press release, complaint, and supporting brief for preliminary injunction.