Liberals fond of griping that the Supreme Court’s conservative Justices are too political should check in with Ruth Bader Ginsburg. The Supreme Court’s oldest Justice sat down with the New York Times on Friday to deplore Republicans and predict a coming liberal ascendancy. “I can’t imagine what the country would be—with Donald Trump as our President,” the Justice averred, adding that the possibility brought to mind her late husband’s advice: “Now it’s time for us to move to New Zealand.”

Justice Ginsburg also ran a victory...