If Donald Trump wins the White House this fall and has a chance to appoint a Supreme Court justice or two in the years that follow — by no means a certain prospect, but one that must be contemplated — his nominees are likely to be quite different than they were during his first term. Everything we know about Mr. Trump today suggests that he will take his judicial cues not from the conservative legal establishment, as he did previously, but instead from the conservative legal movement’s extreme fringes.

During the 2016 presidential campaign, Mr. Trump joined forces with the Federalist Society co-chairman Leonard Leo, who helped assemble a shortlist of conservative judges from which Mr. Trump pledged to select a replacement for Justice Antonin Scalia. Mr. Trump’s decision to publicly align himself with Mr. Leo helped settle the nerves of establishment Republicans who were skeptical of the candidate’s ideological bona fides, and played a significant role in the 2016 election. (One exit poll showed that among voters for whom Supreme Court appointments were the most important issue, 56 percent voted for Mr. Trump.) As president, Mr. Trump selected all his nominees — Neil Gorsuch, Brett Kavanaugh and Amy Coney Barrett — from versions of the shortlist, which he periodically updated.

In the past four years, however, Mr. Trump has soured on the conservative legal establishment. He was reportedly furious with lawyers at the White House and the Justice Department — many of them recommended to him by the Federalist Society — who were, in his view, insufficiently willing to help him overturn the 2020 election results. He felt similarly about Justices Gorsuch, Kavanaugh and Barrett, perceiving their refusals to entertain his various voter fraud cases as disappointing exhibitions of disloyalty.

As a result, Mr. Trump has changed his inner circle of lawyers. As of February, he was reportedly no longer speaking with Mr. Leo or the former White House counsel Don McGahn, two key cogs in his once formidable judicial confirmation machine. The Federalist Society credentials that were once essential for conservative lawyers aspiring to federal judgeships during Republican presidencies are, in Mr. Trump’s world, now apparently a liability.

This shift in Mr. Trump’s judicial brain trust could be disastrous for the country. The sort of far-right candidate who might now appeal to Mr. Trump for the Supreme Court, if confirmed, would make it even easier to overturn Warren court-era decisions that protect cherished constitutional rights. For all the court has already done to lose the public’s trust, the appointments of figures like these would erode whatever legitimacy the institution has left.

In March, Mr. Trump suggested that he’d update his Supreme Court shortlist for a potential second term — by the end of which Justices Clarence Thomas, Samuel Alito and Sonia Sotomayor would have celebrated their 80th, 78th and 74th birthdays — but he has yet to do so. In the meantime, the types of activists who are likely to have Mr. Trump’s ear are busy making lists of their own.