President Trump recently lashed out at Justices Sonia Sotomayor and Ruth Bader Ginsburg. “Both should recuse themselves on all Trump, or Trump related, matters!” he tweeted. He’s wrong about Justice Sotomayor but has a point about Justice Ginsburg.

In a lone opinion dissenting from the court’s order in Wolf v. Cook County, Justice Sotomayor said she wouldn’t stay a lower court’s injunction against a Trump immigration policy. “Claiming one emergency after another,” she wrote, “the Government has recently sought stays in an...