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.

Under cross-examination from defense attorney Abbe Lowell, Hunter Biden's former girlfriend Hallie Biden said some of her memories of their interactions from the time of the gun purchase are vague.

Lowell began his questioning by saying he understood that it was a "fairly upsetting" period and that "being here is no picnic either."

Hallie Biden conceded that "it's difficult to recall" exactly where Hunter was at specific moments or whether he was where he suggested he was, at one point saying that "it's all kind of vague."

"Reconstructing this is not easy?" Lowell asked her.

"Correct," she replied.

Hallie Biden, the widow of Hunter Biden's late brother Beau Biden, testified that the "remnants" of crack she found in Hunter Biden's car on Oct. 23, 2018 -- the day she discovered then discarded the firearm -- could have been from weeks or months earlier.

"You didn't see him doing drugs or alcohol" the day you discarded the gun, Lowell inquired.

"Correct," she said.

At one point Lowell's cross-examination descended into a bit of chaos as both Lowell and Hallie Biden struggled to follow the proper protocols to get her text messages admitted into evidence.

"So far so good," Abbe said at one point.

"Well, no," prosecutor Leo Wise objected.

Jurors rubbed their eyes and gazed around as the back-and-forth continued, with the courtroom bursting into laughter on several occasions. At one point, Hallie Biden appeared to look over at her fiancé sitting in gallery, shrugging her shoulders and appearing to mouth the words "I don't know."

Court was subsequently recessed for lunch.