Both the Supreme Court and Congress — or both — should act to rein in district court judges who issue “nationwide” or “universal” injunctions.

Such injunctions purport to apply those judges’ decisions to the whole country, rather than just to the litigants before them or to the specific geographical jurisdictions the judges serve. The use of such injunctions has exploded in recent years, and it has proven particularly popular among liberal district judges who aim to block initiatives of the Trump administration.

A few weeks back, I made the case that Congress should move to limit the abusive use of such injunctions. Several questioners and panelists at a Feb. 4 Heritage forum said the same thing, noting that Congress does have the authority to define and limit federal court jurisdictions in multiple ways, not just geographically.

But what I had missed was that a Supreme Court precedent from 1984 already should be keeping many of these judges in check. Heritage senior fellow Hans von Spakovsky spent some time discussing that precedent in his opening remarks.

In United States v. Mendoza, a unanimous Supreme Court ruled that one district court’s decision on a particular legal issue was not binding on other district courts. Not a single justice disagreed when Chief Justice William Rehnquist wrote that making a single lower court decision binding against the government in all jurisdictions “would substantially thwart the development of important questions of law by freezing the first final decision rendered on a particular legal issue.”

Rehnquist’s opinion continued:

Allowing only one final adjudication would deprive this Court of the benefit it receives from permitting several courts of appeals to explore a difficult question before this Court grants certiorari. Indeed, if nonmutual estoppel were routinely applied against the Government, this Court would have to revise its practice of waiting for a conflict to develop before granting the Government's petitions for certiorari.

This is a key point. In plain language, it means that the Supreme Court often waits to weigh in, so as to see if there is a difference of opinion on a contested legal issue among lower courts. Because the Supreme Court accepts only about 100 cases a year, this practice helps ensure that it spends its time only on matters where the law really seems murky. It also allows the court to see how the arguments apply in cases with different details, so the justices can see the legal issue from different angles that might illumine their thinking.

These are not, of course, the only reasons such national injunctions can be problematic. As Justice Samuel Alito explained in another case, if a single lower court judge can in effect bind the entire country, it encourages litigants to race to the courts to find a friendly judge. This, he wrote, “invites the losers to seek to obtain in court what they could not achieve in the political arena.”

One way or another, judges should show restraint. But if they won’t, Congress or the Supreme Court should restrain them.