NEW YORK >> The trials of Donald Trump began Monday in a New York courtroom, where the former president made an appearance to fight the first of several government actions against him — a civil case that imperils his company and threatens his image as a master of the business world.

The case, brought by Letitia James, New York’s attorney general, takes aim at Trump’s boasts about his net worth, accusing the former president of crossing from hyperbole into fraud. In some years, the attorney general’s office contends, Trump, his adult sons and their family business inflated his riches by more than $2 billion so that they could secure favorable terms from banks and bragging rights about his overall wealth.

“Year after year, loan after loan, defendants misrepresented Mr. Trump’s net worth,” Kevin Wallace, a lead lawyer for James, said during opening statements on Monday morning. He noted that while it might be one thing to exaggerate for a television audience or Forbes Magazine’s list of the richest people, “you cannot do it while conducting business in the state of New York.”

Just outside the courtroom, Trump fired a fusillade of personal attacks on James and the judge overseeing the case, Arthur Engoron, even suggesting that they were criminals.

Inside, however, Wallace methodically cast doubt on the value of some of Trump’s signature properties, including Trump Tower in Manhattan, laying the groundwork for a reckoning of the former president’s net worth. If the attorney general’s office proves its case, the judge could impose a sweeping array of punishments on Trump, including a $250 million penalty and a prohibition on operating a business in New York ever again.

The trial, expected to last several weeks and to include testimony from Trump, coincides with the former president’s latest White House run. After James’ civil case wraps, Trump will face four criminal trials that touch on a range of subjects: hush-money payments to a porn actor, the handling of classified documents and his efforts to remain in power after losing the 2020 election.

On Monday, Trump sat mostly silent at the defense table, arms crossed and scowling, while occasionally rolling his eyes at the judge and yawning during the duller portions of the proceeding. But he came out swinging on his way into the courtroom, telling reporters that James was out to get him because he is performing so well in the polls.

“You ought to go after this attorney general,” he said, an explicit call to others to join his attacks on James, while also calling Engoron a “rogue judge” who “should be out of office” and the case against him “a witch hunt, it’s a disgrace.”