The Supreme Court heard two hours of arguments Thursday on whether to stay the “universal” injunctions that lower judges have issued to block President Trump’s order reinterpreting birthright citizenship. Echoing through the debate was uneasiness that Mr. Trump might try to game the legal system. After the Abrego Garcia fiasco, it’s hard to blame the Justices for wondering.

The federal government is asking the High Court to pare the injunctions so they protect only the parties who sued. But the Administration reserves the right to deny birthright citizenship to other U.S.-born children of aliens covered by Mr. Trump’s policy. If an appeals court rules the order illegal, Justice Elena Kagan asked, would Mr. Trump keep enforcing it against everyone else in the same circuit?

“I can’t answer, because it would depend on what the lower decision said,” replied Solicitor General John Sauer. “There are circumstances, as I was suggesting, where we think that we want to continue to litigate that in other district courts in the same circuit.”

What if the government keeps losing all the individual cases but refuses to appeal the merits of the birthright citizenship question to the Supreme Court, which could settle it for good? Justice Kagan suggested that would still let Mr. Trump enforce his order against everyone who can’t get to court personally.