When a federal district court in Texas issued a nationwide injunction in 2015 that halted the implementation of President Obama's amnesty program for illegal-alien parents of U.S. citizens, many on the political right cheered. Two years later, when a federal district court in Maryland issued a nationwide injunction that blocked President Trump's efforts to place restrictions on transgender people serving in the military, it was the left's turn to celebrate.

In recent years national injunctions have somehow become all the rage, even though it's not clear they are constitutional. Traditionally, an injunction requires the parties in a case--and only those individuals--to continue or cease particular actions. What makes national injunctions distinct and controversial is that they apply to people who are not parties in the case. And state attorneys general now regularly use them as political cudgels to thwart the implementation of federal policy not just in their respective states, but everywhere.

Sooner or later, I expect, either Congress or the Supreme Court will put the brakes on this practice.  Hopefully sooner.