The former president is facing down Michael Cohen, his longtime fixer, in a Manhattan courtroom, while other ex-loyalists are cooperating in a case against him in Georgia.Donald J. Trump could not hide his anger. Sitting at the front of a crowded New York courtroom this week, he folded his arms tightly across his chest. He tossed his head and scowled. He stared into the middle distance and scrolled through his phone.His ire was directed at Michael D. Cohen, his former personal lawyer and fixer, who had taken the witness stand 15 feet away and had promptly called Mr. Trump a liar. Mr. Cohen has told his share of lies as well. But in court, he swore he had done so “at the direction of, in concert with and for the benefit of Mr. Trump.”Mr. Cohen’s two days of dramatic testimony this week provided the first glimpse of what could become a familiar scene: Mr. Trump, sitting at a defense table, watching as a lawyer who once did his bidding now cooperated with the authorities seeking to hold him to account.On the same day Mr. Cohen began his testimony, Jenna Ellis, who had sought to help Mr. Trump overturn the results of the 2020 election, pleaded guilty to state charges in Georgia. She was preceded by Sidney Powell and Kenneth Chesebro, both lawyers who worked with Mr. Trump’s campaign, both now expected to cooperate in the criminal case that the Georgia prosecutors brought against him.The circumstances surrounding the Georgia criminal case and the Manhattan civil fraud trial are vastly different. But near the center of each case are lawyers who pledged public fealty to Mr. Trump — until they very publicly did not.Mr. Trump has long relied on a phalanx of legal attack dogs to speak on his behalf, or to do or say things he would rather not do or say himself. And because Mr. Trump has such a tenuous relationship with the truth, those lieutenants often spread a message that prosecutors and investigators consider to be outright lies. Lies about an election he lost, a relationship with a porn star he may have had and a net worth he may not quite have achieved.Now those statements are ricocheting back at Mr. Trump as he contends with the civil trial in New York, brought by the state’s attorney general, Letitia James, and with four criminal indictments up and down the East Coast. And while Mr. Trump is quick to blame his betrayers — Mr. Cohen is “proven to be a liar,” he said outside the courtroom this week — his predicament was born from his own lopsided approach to relationships.Mr. Trump has a history of disavowing people who were once close to him and find themselves in trouble. He had long since cut ties with Mr. Cohen — until Tuesday, they had not seen each other in five years — and more recently he distanced himself from the lawyers in the Georgia case. He had also refused to pay their mounting legal bills.Their relationships, a one-way street flowing in Mr. Trump’s direction, appeared to work for a time. But when those loyal soldiers faced their own legal jeopardy, their allegiance to the former president became strained or even shattered.There have been exceptions since Mr. Trump’s split with Mr. Cohen. Mr. Trump’s political action committee has picked up the legal bills for his co-defendants in the federal criminal case involving his handling of classified government documents, as well as those of several witnesses connected to the case.Mr. Trump’s company also agreed to dole out a $2 million severance payment to his longtime chief financial officer, Allen H. Weisselberg, and continues to pay for Mr. Weisselberg’s lawyers. Mr. Weisselberg pleaded guilty to tax fraud and testified at the company’s criminal trial last year, but has stopped short of turning on Mr. Trump.Mr. Cohen was among several in a series of people who Mr. Trump turned to over decades in the hopes they would emulate his first fixer and defender, the lawyer Roy Cohn. “Roy was brutal, but he was a very loyal guy,” Mr. Trump told one of his biographers, Timothy O’Brien, in an interview. “He brutalized for you.”That brutality — along with Mr. Cohn’s method of conflating public relations defenses with legal ones, making showy displays in court and accusing the federal government of “Gestapo-like tactics” against Mr. Trump in a 1970s suit alleging housing discrimination — became Mr. Trump’s preferred model for a lawyer.Mr. Cohen has often said that those sort of tactics influenced what Mr. Trump looks for in those who defend him.While it is unclear how useful Ms. Ellis and the other two lawyers will be to the case against Mr. Trump in Georgia, Mr. Cohen has already been tormenting Mr. Trump for the last five years. Ms. Ellis became critical of him publicly in the last several months.Mr. Trump made a point of attending the trial in Manhattan this week to watch Mr. Cohen’s testimony in person.Dave Sanders for The New York TimesFor Mr. Trump, the feud with Mr. Cohen is personal. Although he is running for president and fighting the four indictments, none of those obligations could pry him away from the Manhattan courtroom to watch Mr. Cohen’s testimony. Mr. Trump did not have to attend the testimony, but people close to him say he believes events go better for him when he is present.Mr. Trump’s falling out with Mr. Cohen stemmed from their dealings with the porn star Stormy Daniels.In the final stretch of the 2016 presidential campaign, Mr. Cohen paid Ms. Daniels $130,000 to silence her story of an affair with Mr. Trump years earlier — an affair that Mr. Trump denied had ever taken place.The deal came to light in 2018, and soon, the F.B.I. had searched Mr. Cohen’s home and office. As Mr. Cohen’s life imploded, Mr. Trump began to distance himself from his fixer, and eventually, his company stopped paying Mr. Cohen’s legal bills altogether.Mr. Cohen soon lashed out and began to speak with prosecutors. When he pleaded guilty that year for his role in the hush-money deal, he stood up in court and pointed the finger at the then-president. Mr. Trump, Mr. Cohen declared, had directed the payment of the hush money.Although the federal prosecutors declined to indict Mr. Trump, this year the Manhattan district attorney’s office brought charges against him related to the deal, using Mr. Cohen as a potential star witness for a trial scheduled to start in the spring. Mr. Cohen has also testified before Congress that the former president’s company had manipulated financial statements to reach Mr. Trump’s desired net worth. That testimony was the catalyst for Ms. James to open her investigation.When Ms. James’s team questioned Mr. Cohen on Tuesday, he repeated many of the same accusations, testifying that Mr. Trump had directed him to “reverse engineer” annual financial statements to reach the former president’s desired net worth.Mr. Cohen spoke calmly and confidently as he recounted Mr. Trump’s obsession with his net worth.But the Trump team’s cross-examination exposed the perils of relying on a disgruntled former aide, especially one as temperamental as Mr. Cohen.Mr. Trump’s lawyers seized on Mr. Cohen’s inconsistent statements about the former president and his own crimes, leading him to admit to having lied a number of times. Toward the end of the second day of cross-examination, Mr. Cohen appeared visibly flustered as he tripped over rapid-fire questions about whether Mr. Trump had personally directed him to inflate numbers on his annual financial statements. Mr. Cohen said he had not, prompting Mr. Trump and one of his lawyers, Alina Habba, to throw their hands up in victory.Ms. Habba also resurfaced a series of glowing remarks Mr. Cohen once made about his boss, further underscoring his about-face.“I think he’s going to be an amazing president”; “I’m the guy who would take the bullet for the president”; “I think the world of him, I respect him as a business man and I respect him as a boss,” Ms. Habba emphatically read, as she circled the courtroom with a hand-held microphone like a preacher delivering a sermon.This appeared to delight Mr. Trump, who turned to watch Ms. Habba while draping his arm over her empty chair.Before Mr. Cohen completed his testimony on Wednesday, one of Mr. Trump’s lawyers asked Justice Arthur J. Engoron to dismiss the case, citing Mr. Cohen’s contradictions.Justice Engoron denied the request, and Mr. Trump stormed out of the courtroom.Kate Christobek More