Donald Trump and his co-defendants have filed a motion seeking a mistrial on the grounds that the trial has been "tainted" by the appearance of bias on the part of Judge Arthur Engoron and his law.

"This appearance of bias threatens both Defendants' rights and the integrity of the judiciary as an institution," Trump's attorneys say in the filing. "As developed herein, in this case the evidence of apparent and actual bias is tangible and overwhelming."

"Specifically, the Court’s own conduct, coupled with the Principal Law Clerk, Allison Greenfield’s unprecedented role in the trial and extensive, public partisan activities, would cause even a casual observer to question the Court’s partiality," they write.

"Such evidence, coupled with an unprecedented departure from standard judicial procedure, has tainted these proceedings and a mistrial is warranted," the filing says.

Donald Trump's lawyers are scheduled to resume their direct examination of expert witness Jason Flemmons this morning, continuing a line of questioning yesterday that largely placed responsibility for Trump's financial statements on Trump's external accountants.

Flemmons, who was qualified as an expert on accounting, explicitly criticized the testimony of Donald Bender, Trump's accountant at Mazars USA who was the New York attorney general's first witness, disputing Bender's claim that he would have wanted to see any appraisals that the Trump Organization conducted.

Flemmons also testified that Trump's financial statements should have sent a "buyer beware" signal to lenders due to the "highly cautionary language" in their disclaimer, which allowed Trump to make claims that significantly departed from generally accepted accounting principles.

To the extent that the statements and the Trump Organization's representations about the statements were inaccurate, Flemmons placed responsibility on Bender and his colleagues at Mazars, rather than the Trump Organization.

Expert witness Jason Flemmons cast doubt on the testimony of the Trump Organization's former external accountant Donald Bender, who said he would have wanted to review any appraisals that the Trump Organization conducted.

"That's not something that is required by professional standards," said Flemmons, testifying for the defense. "His testimony was not professionally plausible."

That prompted a strong objection from state attorney Kevin Wallace.

"Is he trying to say the witness is lying?" Wallace said.

"Not to put too fine a point on it," Judge Engoron quipped.

Asked to confirm what he meant by "professional plausible," Flemmons said it would be "highly unusual" for Bender to request appraisals outside what was mentioned in the statement of financial condition.

"Accountants in the industry do not go seeking records for things that are not in the four corners of the statement of financial condition," Flemmons said.

Court was subsequently adjourned for the day, with Flemmons scheduled to continue his testimony tomorrow.

Defense expert Jason Flemmons described the disclaimer included in Donald Trump's financial statement as the "highest level disclaimer" that could have been provided to bankers reviewing the document.

Flemmons said that the disclaimer, which he said includes "highly cautionary language," would allow a user to make claims that significantly departed from generally accepted accounting principles, known in the industry as GAAP.

"Was that language present in a substantially similar form in the compilation statements issued by Mazars for Donald Trump?" defense attorney Jesus Suarez asked.

"Yes," Flemmons said, adding that the disclaimer was "effectively saying 'user beware.'"

During his testimony and in statements to the media, Trump has claimed that the disclaimer shields him from liability in the case.

Suarez also used Flemmons' testimony to suggest that Trump's external accountants were responsible for understanding the methods used in the financial statement and determining their appropriateness.

That appeared to conflict with testimony of former Trump accountant Donald Bender of Mazars USA, who described his role as akin to plugging numbers provided by the Trump Organization into a template.

Former President Donald Trump's plan to deliver part of his closing argument Thursday, as reported yesterday by ABC News, is now in doubt after he failed to meet a deadline to agree to limitations imposed by Judge Arthur Engoron.

According an email exchange between Engonon and defense counsel that was posted to the public docket Wednesday, Engoron said that Trump would have to follow the case's limited gag order, and that he would not be allowed to "impugn" the New York attorney general or her staff -- limitations that Trump attorney Chris Kise rejected, calling them "untenable."

"The limitations I am imposing, in my absolute discretion, are not subject to further debate. Take it or leave it," Engoron replied on Jan. 9, according to the email thread.

When Trump's lawyers missed the first deadline set by Engoron, the judge determined that Trump could not testify. Kise then responded that he did not see the deadline and requested that the closing arguments be postponed because of the death of Melania Trump's mother on Tuesday.

"I am sad to advise the Court that Mrs. Trump's mother passed away this evening. Because of the challenges presented by this deeply personal family matter, President Trump has asked that I request the Court postpone the date for closing argument," Kise wrote yesterday.

Engoron promptly denied the request and said the closings would continue as planned.

"On balance, going forward makes the most sense. Please tell Mr. Trump that I am sorry," Engoron wrote.

Kise informed Engoron that Trump still planned to attend the closings and speak.

"Despite the fact that his Mother-in Law, who he was very close to, passed away late last night, President Trump will be speaking tomorrow," Kise said in an email this morning.

When Engoron asked for assurance that Trump agreed to his rules, Kise pushed back, writing, "You are not allowing President Trump, who has been wrongfully demeaned and belittled by an out of control, politically motivated Attorney General, to speak about the things that must be spoken about."

"I won't debate this yet again. Take it or leave it. Now or never. You have until noon, seven minutes from now. I WILL NOT GRANT ANY FURTHER EXTENSIONS," Engoron replied at 11:54 a.m.

After Kise failed to respond, Engoron emailed him at 12:12 p.m. that he assumed Trump would not be speaking and that their email exchange would be posted to the court's public docket.

Responding to the development, Trump's legal spokesperson, Alina Habba, said in a statement to ABC News: "Is anyone surprised anymore?"