President Trump’s broadside on Truth Social against the Federalist Society and its longtime leader, Leonard Leo — after a Federalist Society-approved judge was one of three jurists who issued a ruling blocking Mr. Trump’s signature tariffs initiative — is a shocking rupture between America’s preeminent conservative legal group and the Republican president.

Mr. Leo, the chairman of the Federalist Society’s board of directors and its former vice president, is by many measures the nation’s most powerful conservative legal activist. He is widely credited with a role in placing Justices Clarence Thomas, Samuel Alito, Neil Gorsuch, Brett Kavanaugh, Amy Coney Barrett, and Chief Justice Roberts on the Supreme Court. 

The Federalist Society supports an originalist or textualist approach to elucidating the Constitution. It  has long been at the nexus of conservative legal thought. The society has a presence at more than 200 law schools and counts some 70,000 members. Justices Gorsuch, Kavanaugh, and Barrett were all placed on the court during Mr. Trump’s first term.

They were, moreover, all recommended by Mr. Leo and the Federalist Society, part of whose remit is developing a pipeline of conservative judges and a list of prospective Supreme Court justices to aid the president in filling vacancies on the high court as well as across the federal judiciary. 

One of the signal achievements of Mr. Trump’s first term, in the eyes of conservatives, was how he appointed scores of conservative judges — at the district, circuit, and Supreme Court tiers — at an unprecedented pace, securing their confirmations to the federal bench with lifetime appointments.

The trigger for Mr. Trump’s ire was a ruling by the Court of International Trade that the president exceeded his authority when he imposed a raft of “reciprocal” tariffs on “Liberation Day.” One of the three judges who ruled against Mr. Trump was Timothy Reiff, a Democrat whom the president named to the bench. The permanent injunction against the tariffs was stayed by the United States Court of Appeals for the Federal Circuit pending a decision on the merits. 

Mr. Trump, though, is still angry at the lower court and blames Mr. Leo and the Federalist Society. Mr. Trump recalls when he was “new to Washington, and it was suggested that I use The Federalist Society as a recommending source on Judges. I did so, openly and freely, but then realized that they were under the thumb of a real ‘sleazebag’ named Leonard Leo, a bad person who, in his own way, probably hates America.”

The 47th president ventures that Mr. Leo — famous for preferring to stay behind the scenes — “openly brags how he controls Judges, and even Justices of the United States Supreme Court — I hope that is not so, and don’t believe it is!” Mr. Trump adds that he is “so disappointed in the Federalist Society because of the bad advice they gave me on numerous Judicial Nominations.” Every conservative justice on the Supreme Court has had some affiliation with the Federalist Society. 

Mr. Trump allowed that he is “very proud of many of our picks, but very disappointed in others.” That ambivalence could be exacerbated by the intermittent resistance to his agenda mounted by the Supreme Court — in particular by the last justice he appointed, Justice Barrett. She voted with the court’s liberals to block his freezing of federal expenditures and to enjoin his use of the 1798 Alien Enemies Act. 

Mr. Leo declares in a statement after Mr. Trump’s broadside that he is “very grateful for President Trump transforming the Federal Courts, and it was a privilege being involved. There’s more work to be done, for sure, but the Federal Judiciary is better than it’s ever been in modern history, and that will be President Trump’s most important legacy.”

One indication that Mr. Trump could be prepared to go his own way on judicial appointments is his nomination of his  principal associate deputy attorney general, Emil Bove, to fill a vacancy on the Third United States Appeals Circuit. Mr. Bove served as one of Mr. Trump’s defense attorneys during the criminal prosecutions of the 45th president, and took the lead in the Department of Justice’s bruising — and ultimately successful — effort to dismiss federal bribery charges that were handed up against Mayor Adams. 

The true test of Mr. Leo’s influence — or lack thereof — could be if Mr. Trump is presented with another Supreme Court vacancy. The president’s broadside against Mr. Leo could, possibly, deter even a conservative justice close to the judicial kingmaker from retiring — and leaving a space open for Mr. Trump to eschew the Federalist Society’s recommendations altogether.

Mr. Trump’s criticism of Mr. Leo and the Federalist Society comes as his attorney general, Pam Bondi, informed the American Bar Association that the DOJ is cutting its access to judicial nominees, ending its prior, privileged role in the vetting process and barring nominees from cooperating at all. In a letter to the group’s president, William Bay, she urged it to “fix the bias in its rating process.” Conservatives have long criticized the ABA as favoring the left.  

That’s not an issue with the Federalist Society, which takes as its guiding charter 78 Federalist, written by Alexander Hamilton. “It can be of no weight to say that the courts, on the pretense of a repugnancy, may substitute their own pleasure to the constitutional intentions of the legislature. … The courts must declare the sense of the law,” 78 Federalist argues.