"One thing I know a lot about is the legal definition of fraud," Justice Arthur Engeron said as he gaveled court into session prior to the start of opening statements.

Engoron opened the proceedings after allowing cameras in to document the scene in the courtroom: Trump, arms folded, flanked by his legal team; Engeron on the bench; and throngs of reporters and spectators in the gallery.

"I've promised to do my best despite my lame attempts at humor," Engeron said in a brief opening statement. "I take my job very seriously."

The trial is expected to last through Dec. 22, Engeron said, and suggested he would attempt to keep a low profile after today.

"For the next three months, I hope the only words I will mutter are 'Sustained,' 'Overruled,' and 'Let's take a 10-minute break,'" he said.

Opening statements are underway in former President Trump's $250 million fraud trial.

Trump is seated between his attorneys Clifford Robert, Alina Habba and Christopher Kise.

Trump and his co-defendants face a bench trial, meaning that the sole arbiter of the case is Judge Arthur Engoron instead of a jury.

Former President Trump has taken a seat in the courtroom for the start of the trial.

"The crime is against me," he told reporters outside the courtroom before he made his way inside.

He denounced the case in now-familiar terms, criticizing state Attorney General Letitia James as she sat inside the courtroom.

Trump also accused Judge Arthur Engoron of failing to account for the full value of his real estate portfolio, asserting his Mar-a-Lago estate is worth "50 to 100 times more" than the judge's decision for partial summary judgment said last week.

"We have other properties, the same thing. So he devalued everything," Trump said. "We have among the greatest properties in the world. and I have to go through this for political reasons."

Engoron decided Trump's statements of financial condition were fraudulent, but Trump said, "We have a clause in the contract that says, essentially, buyer beware."

Former President Trump, speaking to reporters on his arrival at the lower Manhattan courthouse, said the trial is a witch hunt resulting from his standing in the presidential polls.

"This is a continuation of the greatest political witch hunt of all time," he told reporters outside the courtroom.

Trump said he is innocent of the accusations and that his portfolio has a much higher value than what the attorney general alleges.

Taking the witness stand as an expert witness for the defense, accountant Jason Flemmons offered testimony in support of Donald Trump's approach to valuing his Mar-a-Lago property, which has been the subject of debate throughout the seven weeks of the trial.

In his summary judgment decision, Judge Engoron found that Trump overvalued the estate by at least 2,300% because the Palm Beach County Assessor appraised the property's market value between $18 and $27.6 million after Trump signed a deed that restricted its use to a social club, potentially limiting its resale value as a residence but ensuring a tax cut. Trump, in contrast, listed its value in his financial statement between $426 million and $612 million, and during his appearances in court and online he has repeatedly attacked Engoron's finding.

Flemmons argued that Trump's approach to valuing his assets gave him latitude to consider his property's future revenue streams. That approach, according to Flemmons, could result in "wildly different values" between the numbers listed on a personal financial statement and a tax assessed value.

"Tax assessed values are typically on the lower end of the spectrum," Flemmons said, while Engoron looked on attentively.

While he never mentioned Mar-a-Lago by name, Flemmons was asked by defense attorney Jesus Suarez about a hypothetical property assessed at $18 million but valued closer to $500 million using a comparable sales approach -- the same approach used to value Mar-a-Lago.

"It would not be unusual to have a value in the hundreds of million using projected cash receipts," Flemmons said.

Engoron then turned his chair toward Flemmons and began asking his own questions.

"I am trying to get to the order of magnitude we are talking about here," Engoron said. "What is the highest value you have ever seen legitimately placed on such a property?"

Flemmons could not provide a specific example to answer Engoron's question but reiterated that a massive discrepancy could be appropriate.