The People of the State of New York v. Donald J. Trump, et al, is scheduled to get underway in lower Manhattan at 10 a.m. with opening statements.

If opening statements are completed before the end of the day, the New York attorney general plans to begin her case by calling Trump's former Mazars USA accountant Donald Bender to the stand.

Mazars severed its business relationship with the former president last year after learning of the attorney general's findings during the AG's probe.

Though Trump has denied all wrongdoing alleged by the attorney general, Judge Arthur Engoron has already decided the central allegation against Trump and his co-defendants, ruling in a pretrial hearing last week that the AG had provided "conclusive evidence" that Trump overvalued his assets between $812 million and $2.2 billion.

The judge then canceled the Trump Organization's business certificates in New York, severely restricting Trump's ability to conduct business in the state moving forward -- a move that Trump attorney Alina Habba called "nonsensical" and "outrageously overreaching."

"In defendants' world: rent regulated apartments are worth the same as unregulated apartments; restricted land is worth the same as unrestricted land; restrictions can evaporate into thin air," Engoron wrote, citing multiple arguments made by defense to justify the allegedly inflated valuations of Trump's assets. "That is a fantasy world, not the real world."

Among the issues still to be determined at trial: What additional penalties Trump might face, and what might happen with the multiple causes of action included in the attorney general's suit.

Former President Donald Trump stepped up his attacks on the judge overseeing and deciding his case, writing on Truth Social overnight that Justice Arthur Engoron should resign and be sanctioned for "abuse of power."

Similar to an earlier post, Trump criticized allegations regarding the value of his Mar-a-Lago estate, in addition to an appellate court's ruling that his lawyers unsuccessfully tried to use to limit the timeframe of the case.

Former President Trump posted on his Truth Social platform Sunday night that he intends to attend the opening of the trial.

"See you in court -- Monday morning," he wrote in a post.

Earlier Sunday, multiple sources familiar with the decision told ABC News that Trump was expecting to attend.

Trump will have no speaking role in court on Monday, but it is anticipated that he'll return to the courthouse toward the end of the state's case when court records show he will be called as a witness.

Defense attorney Chris Kise requested that Judge Engoron again reconsider his decision to fine Donald Trump $10,000 for violating the case's limited gag order yesterday, offering a broader criticism of the gag order based on First Amendment grounds.

"This is open, public, and the defendant has a First Amendment right to comment on what he sees and perceives as a potential source of bias," Kise said.

Like yesterday, Kise maintained that Trump was referring to Michael Cohen, rather than the judge's law clerk, during his hallway statement in which he said the judge has a "person who is very partisan sitting alongside of him." Trump attested to this on the stand yesterday, though Engoron found that Trump was "not credible."

"The review of the statement does not support the sanction," Kise said.

Even if Trump was referring to the clerk, Kise made a broader argument that the gag order itself was "constitutionally infirm," considering Trump is the "leading candidate" for the presidency.

"I don't think that the order survives constitutional scrutiny," Kise said.

State attorney Andrew Amer argued in support of the gag order, which he said was narrowly limited to withstand constitutional scrutiny.

"A federal judge in D.C. has issued a similar order to protect herself," Amer added, referring to a ruling in Trump's election interference case.

Judge Engoron said he would reconsider the fine but stood by his gag order.