The attorney general of New York state is seeking $20,000 in sanctions against Donald Trump, his adult sons, other defendants and their lawyers, for repeating “frivolous” arguments rejected in court in a $250m civil suit over family business practices. In a filing on Tuesday, Andrew Amer, an assistant to Letitia James, the attorney general, noted repeated rejections of arguments deemed “borderline frivolous even the first time defendants made them”. Amer also noted a previous observation by the judge in the case that “reading [the] defendants’ brief ‘was, to quote the baseball sage [Yogi] Berra, deja vu all over again’.” Berra was a New York Yankees catcher and manager whose garbled sayings – also including “It ain’t over till it’s over” and “You can observe a lot by watching” – somehow seemed to make sense. James thinks she has made sense of how defendants including Donald Trump, Donald Trump Jr and Eric Trump played fast and loose with both the true state of the former president’s finances and with New York corporate law. Last week, filings in an attempt to resolve the case without trial showed prosecutors’ contention that annually between 2011 and 2021 Trump inflated his net worth by between $812m and $2.2bn. The judge has not ruled on that filing. Trial is set for October. In the filing on Tuesday, James’s assistant also noted the judge’s ability to impose financial penalties for conduct deemed frivolous if because without merit in law or pursued to delay a case. In January, rejecting a Trump attempt to dismiss the case, the judge, Arthur Engoron, said some arguments repeatedly deployed by Trump lawyers were “frivolous”. But after deploying his Yogi Berra quote, Engoron said that though “sophisticated defense counsel should have known better”, he would not “impose sanctions, which the court believes are unnecessary, having made its point”. James now believes the point needs to be backed by sanctions. Engoron has sanctioned Trump before. In early 2022, the former president paid $110,000 in fines, after failing to meet case deadlines. Not all Trump’s adult children are involved in the New York suit. In June this year his oldest daughter, Ivanka Trump, was dismissed from the case. It is not the only civil suit Donald Trump faces. He also faces a second defamation trial involving the writer E Jean Carroll, who said he sexually assaulted her in the 1990s. Found liable for defamation and sexual abuse, Trump was already fined about $5m and adjudicated a rapist. In other courtrooms, Trump faces 91 criminal charges under four indictments. The counts cover hush-money payments to a porn star (34); retention of classified information (40); and attempted election subversion at federal (four) and state (13) levels. Denying all wrongdoing, Trump claims to be the victim of political persecution. That argument seems effective with Republican voters, stoking huge leads in national and key state polling regarding the next nomination for president.