Hunter Biden has arrived at the courthouse for the start of his federal gun trial this morning.

His stepmother, first lady Jill Biden, is attending the proceedings.

Two hundred and fifty Delaware residents have been summoned to the courthouse in downtown Wilmington, where they will face typical questions about their fitness to serve as jurors.

But because this is the trial of the son of a sitting president, there will be some novel topics covered during the jury selection process known as "voir dire."

Among the questions jurors will be asked: "If you were eligible to vote in any election(s) in which Joseph R. Biden was a candidate, would that fact prevent you from maintaining an open, impartial mind until all of the evidence is presented, and the instructions of the Court are given?"

And "Do you believe Robert Hunter Biden is being prosecuted in this case because his father is the President of the United States and a candidate for President?"

On the eve of trial, U.S. District Judge Maryellen Noreika threw a wrench in one of the key arguments attorneys for Hunter Biden were planning to advance, ruling that an annotated copy of the federal form Hunter Biden is accused of lying on would be excluded from evidence.

The original document, called an ATF Form 4473, was created in 2018 when Hunter Biden purchased the firearm. But in 2021, gun store employees made a copy that included some handwritten notes. Defense attorney Abbe Lowell contended that employees had "tampered with" the document, and that it raised questions about "who wrote what on the form, and when."

Lowell hoped his argument would undermine the credibility of some key government witnesses -- the people who sold Biden the gun -- and potentially create a reasonable doubt that Hunter Biden was the one who actually checked that box.

Attorneys for special counsel David Weiss' office have said the gun shop employees merely "annotated" the form and urged Noreika to prevent Lowell from introducing it into evidence.

Late Sunday, Noreika sided with Weiss.

Jury selection is scheduled to get underway today in the federal gun trial of Hunter Biden, who authorities say broke the law when he purchased a Colt revolver in 2018.

President Joe Biden's son faces two counts of making false statements while purchasing the firearm and a third count of illegally obtaining it while addicted to drugs.

Although the charges together carry a possible sentence of up to 25 years, legal experts say that, as a first-time and nonviolent offender, Hunter Biden would not likely serve time if convicted.

The trial, in Delaware federal court, is expected to last two to three weeks.

Defense attorney Abbe Lowell, cross-examining Hunter Biden's former girlfriend Zoe Kestan, sought to renew his argument that Hunter Biden was not actively using drugs in October 2018 by emphasizing that Kestan wasn't in contact with him at that time and would not know.

Kestan testified that she wasn't in touch with Hunter Biden from Sept. 23, when they were in Malibu together, until November, when he summoned her to Massachusetts while he was trying out a new ketamine therapy program.

As such, Kestan testified she had "no idea" that he had gone back to Delaware, or what he was doing at that time.

"So you didn't see him between those two dates?" Lowell asked.

"No," she said.

Lowell also sought to cast Kestan as an enabler of Hunter's addiction.

"You helped him get drugs?" Lowell asked.

"Yes," Kestan responded.

Prosecutors pushed back on that argument by highlighting their significant age gap: Kestan was 24 at the time of the relationship, while Hunter Biden was 48.

"Twice my age," she testified.

Kestan subsequently concluded her testimony and stepped down from the witness stand. Prosecutors then prepared to called to the stand Gordon Cleveland, the gun shop employee who sold Hunter Biden the firearm in 2018.