Is this strike two for President Trump? That seems like the subtext of the ruling at home plate by America’s constitutional umpire, Chief Justice Roberts, after the president’s demand to impeach an unfriendly federal judge. That’s “not an appropriate response,” the chief justice says in a rare public statement. It follows the rebuke of Mr. Trump in 2018 by the chief justice, who averred then that there were no such things as “Obama judges or Trump judges.”

These criticisms of the president came despite the assurance that “judges are not politicians,” as Chief Justice Roberts put it in 2005 to the senators weighing his confirmation. “Judges are like umpires. Umpires don’t make the rules, they apply them.” He pledged to “remember that it’s my job to call balls and strikes, and not to pitch or bat.” He reasoned that “nobody ever went to a ball game to see the umpire.”

Yet Mr. Trump’s comments about impeaching a federal district judge, James Boasberg, who ruled against the deportation of alleged Tren de Aragua gang members, compelled the umpire-in-chief to get in the proverbial game. “For more than two centuries,” the chief justice said, “it has been established that impeachment is not an appropriate response to disagreement” over court rulings. “The normal appellate review process exists for that purpose.”

These columns have marked a caution about federal judges risking the appearance of partiality in their handling of cases relating to the Trump administration. Federal judges, after all, swear an oath not only to “support and defend” the Constitution, but to “administer justice without respect to persons,” including the president. Yet the chief justice is right to cry foul amid the reckless talk of impeachment as a response to disagreeable rulings.

“Corrosive to the republic,” is how the Journal, in one of two important editorials on this head, characterized the push to unseat judges. That hasn’t stopped some House members from introducing articles of impeachment. Such talk is no less corrosive coming from Mr. Trump, who calls Judge Boasberg a “Radical Left Lunatic.” He adds: “This judge, like many of the Crooked Judges I am forced to appear before, should be IMPEACHED!!!”

Yet the chief justice hasn’t confined his criticism to Mr. Trump. When Senator Schumer in 2020 fulminated outside the high court that conservative justices “have released the whirlwind” and would “pay the price,” the chief piped up in reply. “Justices know that criticism comes with the territory,” Chief Justice Roberts admonished, “but threatening statements of this sort from the highest levels of government are not only inappropriate, they are dangerous.” 

The chief justice’s attempts to play umpire in the political arena, though, have done little to change the state of play. His criticism of Mr. Schumer, say, failed to stem the tide of the Democrats’ crusade against the high court’s legitimacy. This full-court press, which has even questioned the integrity of the conservative justices, amounted to what Justice Samuel Alito has called a “campaign to try to intimidate the court.”

Amid protests outside the justices’ houses, Justice Alito warned that the court’s conservatives “were really targets of assassination.” The arrest of a troubled young man outside Justice Brett Kavanaugh’s home underscored these concerns. Yet Democratic solons laughed off these fears. “There’s this thing called free speech,” Senator Hirono jeered. Threats and personal attacks on judges are just as pernicious coming from the right as they are from the left.

Which brings us back to Mr. Trump and the furor over Judge Boasberg. Despite the judge’s rulings against Mr. Trump on the use of the Alien Enemies Act to deport foreign nationals, these columns have noted that the president has a strong case to be made for his position before the Supreme Court. To short-circuit that process by pursuing impeachment rather than appealing to higher courts, a judicial umpire might say, would be an unforced error.