On a balmy Saturday night in June, Traci Lovitt hosted a 50th birthday party for her husband, Ara, at their 9,800-square-foot Westchester mansion overlooking Long Island Sound. The couple met while clerking for Supreme Court justices: Traci for Sandra Day O’Connor, Ara for Antonin Scalia. These days, Ara worked in finance. Traci was a top partner at — and a contender to one day run — the international law firm of Jones Day, best known for representing Donald Trump’s presidential campaigns. To serve as M.C. for the event, the Lovitts flew in Richard Blade, the veteran disc jockey Ara listened to while growing up in Southern California. But Blade wasn’t the party’s biggest star. That distinction belonged to Justice Amy Coney Barrett.One day earlier, Barrett and four of her colleagues on the Supreme Court overturned Roe v. Wade, ending the constitutional right to abortion. Now she was wearing a pink dress and sitting at a flower-bedecked table under a tent on the Lovitts’ lush lawn. Barrett clerked for Scalia in the same session as Ara, in 1998 and 1999, and also became friends with Traci, jogging together around the National Mall after work. (When Trump nominated Barrett to the Supreme Court in 2020, Traci wrote to senators, praising the judge’s fair-mindedness and commitment to the rule of law.) But the connection to the court ran deeper than that. Scalia had spent years at Jones Day in the 1960s. And Traci ran an elite practice inside the firm that was focused in part on arguing cases before Barrett and her colleagues. Guests at the Lovitts’ estate danced to Blade’s beats until 1 a.m. At one point, an attendee spotted Barrett chatting with Noel Francisco, another Jones Day partner, who had himself clerked for Scalia the year before Lovitt and Barrett. Francisco left the firm in 2017 to become Trump’s solicitor general, responsible for representing the government before the Supreme Court, and returned in 2020, eventually taking over Jones Day’s enormous Washington office. Now his and Lovitt’s underlings were appearing regularly before the court. In one recent case brought by Jones Day, the court killed the Biden administration’s moratorium on home evictions during the pandemic. Less than a week after the Lovitts’ party, in another case Jones Day worked on, the court would severely limit the Environmental Protection Agency’s regulation of power-plant emissions.For much of its history, Jones Day was a juggernaut in the field of corporate litigation. A global goliath with more than 40 offices and about 2,500 lawyers, it raked in billions a year in fees from tobacco, opioid, gun and oil companies, among many other giant corporations in need of a state-of-the-art defense. More than most of its competitors, the firm had an army of litigators who had perfected the art of exploiting tiny legal wrinkles, of burying outmatched opponents in paperwork and venue changes and procedural minutiae. But over the past two decades, Jones Day has been building a different kind of legal practice, one dedicated not just to helping Republicans win elections but to helping them achieve their political aims once in office. Chief among those aims was dismantling what Don McGahn — the Jones Day partner who helped run Trump’s campaign and then became his White House counsel — disparagingly referred to as the “administrative state.” To do that, the firm was bringing all the ruthless energy and creativity of corporate law to the political realm.Jones Day lured dozens of young Supreme Court clerks, mostly from conservative justices, with six-figure signing bonuses and the opportunity to work on favored causes, including legal challenges to gun control and Obamacare. The firm allotted countless pro bono hours to aiding the needy — and also to assisting deep-pocketed right-wing groups as they fought against early voting and a federal corporate-oversight body.Representing Trump’s 2016 campaign, Jones Day helped him solidify Republican support by pledging to pick federal judges from a list that was vetted in advance by the law firm and the Federalist Society. When Trump won, a large fleet of Jones Day lawyers sailed into his White House, the Justice Department and other parts of his administration. But the biggest impact was on the judiciary. Trump delegated the task of selecting federal judges to McGahn, who — working closely with Senator Mitch McConnell, the majority leader — placed well over 100 conservatives on the federal courts, including several who had recently worked at Jones Day. Even after rejoining Jones Day in 2019, McGahn continued to advise Senate Republicans on judicial strategy.It is not uncommon for partners at corporate law firms to dabble in politics. Nor is it rare for a firm itself to throw its weight behind causes on the left or the right. One of the country’s richest firms, Paul, Weiss, for example, has long staked out liberal stances on the public issues of the day (even as it rakes in fees from companies that undercut those ideals). What sets Jones Day apart is the degree to which it penetrated the federal government under Trump and is now taking advantage of a judicial revolution that it helped set in motion.The power of that revolution, which is spreading to courtrooms and statehouses around the country, is now on vivid display. Even with Democrats controlling the White House and Congress, the Supreme Court has been on a rightward tear. In its most recent term, Trump’s three appointees — the first two handpicked by McGahn and the third, Barrett, plucked by him out of academia for the federal bench — helped erase the constitutional right to abortion, erode the separation of church and state, undermine states’ power to control guns and constrain the authority of federal regulators. Jones Day had a hand in some of those cases, and the firm has telegraphed that it is eyeing additional legal challenges in line with its leaders’ ideology.Jones Day’s influence seems poised to grow. This year, it has been collecting fees from a remarkable assortment of prominent Republican players: a Trump political-action committee; moderates like Senator Susan Collins; Trump allies like Dr. Mehmet Oz; hard-liners like Representative Kevin McCarthy of California, the House minority leader, and Senator Ron Johnson of Wisconsin — not to mention an assortment of super PACs supporting fringe candidates like Herschel Walker, the former N.F.L. star who is running for a Senate seat in Georgia. Francisco recently represented former Attorney General Bill Barr before the House committee investigating the Jan. 6 attack on the Capitol. McGahn recently began representing Senator Lindsey Graham as he fights a grand jury subpoena to testify about Trump’s efforts to overturn the election results in Georgia. The chief of staff to Gov. Ron DeSantis of Florida is a recent Jones Day alum. The next Republican presidential administration — whether it belongs to Trump, DeSantis or someone else — will most likely be stocked with Jones Day lawyers.Founded in Cleveland in 1893, Jones Day was at the vanguard of an era of breakneck expansion in the legal industry. In the 1970s and ’80s, it was one of the first law firms to open multiple offices in the United States and then overseas. It was a tireless, and extremely successful, defender of some of America’s worst corporate actors. The firm helped R.J. Reynolds sow doubts about the dangers of cigarettes. It helped Charles Keating’s fraud-infested savings-and-loan association fend off regulators. It helped Purdue Pharma protect its patents for OxyContin. But it didn’t become a conservative machine until Stephen Brogan took over as managing partner in 2003.Brogan, the son of a New York City police officer, joined Jones Day straight out of the University of Notre Dame’s law school in 1977 and, aside from a two-year stint in the Reagan Justice Department, has worked there ever since. A number of Brogan’s allies said the key to understanding him and his politics was through his faith. “Brogan is extremely conservative, hard-core Catholic, and that is the bedrock of who he is,” one of his Jones Day confidants told me. Brogan brought on a series of high-profile devotees of the Federalist Society — including leading Reagan and Bush administration lawyers like Michael Carvin and Noel Francisco — to work in the firm’s issues-and-appeals practice, which became a sort of in-house conservative think tank. Even as most of the firm’s lawyers remained focused on bread-and-butter work for big companies, Jones Day took on a growing list of ideologically charged cases and causes, including efforts by the ultraconservative Buckeye Institute to prevent the expansion of early voting in Ohio and challenge the legitimacy of the Obama administration’s newly inaugurated Consumer Financial Protection Bureau. By 2014, when a trio of Republican lawyers at Patton Boggs, a Washington law firm that was in financial trouble, began looking for a new home, Jones Day was a natural fit. It was huge, it had a thriving Washington office and its leaders were conservative. Plus, the Patton Boggs crew — McGahn, Ben Ginsberg and William McGinley — would fill a void. While Jones Day had built up a formidable practice advising companies on how to navigate the federal bureaucracy, the firm didn’t have a practice advising politicians on how to navigate election and campaign-finance laws. And without the relationships that came from helping people win office, it was harder for Jones Day to wield influence on Capitol Hill and in the White House. It helped that Ginsberg, who had been the top lawyer on presidential campaigns by George W. Bush and Mitt Romney, had known Francisco and Carvin for years. During the interview process, Ginsberg told Francisco that he recognized that Jones Day, despite its conservative reputation, probably employed a lot of Democrats. Would it be a problem to bring in a team that would represent polarizing Republicans? It would not, Francisco assured him. Indeed, promoting conservative principles was becoming part of the firm’s marketing pitch. “The government’s tentacles invade virtually every aspect of what our clients do,” Francisco said in a Jones Day promotional video in 2015. “The job of a lawyer and the job of courts is to ensure that the federal government lives within the limits that our Constitution sets, and I love making sure that those lines are enforced.” Ginsberg and McGahn were well known throughout the Republican establishment, and several would-be presidents soon came to them seeking counsel; Govs. Scott Walker of Wisconsin, Rick Perry of Texas and Chris Christie of New Jersey would become clients. McGahn — who had recently served on the Federal Election Commission, watering down campaign-finance rules and slowing the agency’s decision-making in what he said was an effort to make it more responsive to the people and groups it regulated — also represented a who’s who of other G.O.P. power players: the Republican National Committee, the National Rifle Association, the billionaire Koch brothers.There was at least one other key client: Citizens United. The group, famous for its successful Supreme Court challenge of campaign spending restrictions, was run by Dave Bossie, an influential right-wing activist. One day in late 2014, Bossie and McGahn were on the phone, batting around ideas about which presidential campaigns the Jones Day lawyers should work for.The Trump InvestigationsCard 1 of 6The Trump InvestigationsNumerous inquiries. More