As it tends to do when not in political control in Washington, the Left has rediscovered the power of state sovereignty. That doctrine is being used to resist the new administration's federal immigration policy in a way that's identical, in formalistic terms, to the Right's tactics during the early days of the Obama administration—albeit in service of an opposite outcome.
Granted, when they held the White House and congressional majorities, those on the Left did their best to destroy the principle of state sovereignty as a check on federal power, but perhaps constitutionalists should let bygones be bygones. After all, the Right can hardly claim consistency on this score. Rather than revisit past disputes, constitutionalists should seize the moment of cross-ideological support for state sovereignty. We should enlist the Left in a mutual spirit of opportunism to revive the Supreme Court's holding in the 41-year-old case of National League of Cities v. Usery.