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.

On redirect examination of FBI Special Agent Erika Jensen, prosecutor David Hines heavily pushed back on the defense's suggestion that no text messages showed Hunter Biden buying drugs during the time he purchased a gun, and their contention that his large cash withdrawals could have been for other purposes.

Hines returned to the key text message Hunter sent while he owned the gun, telling his then-partner Hallie Biden that he was "sleeping on a car" smoking crack.

"You understand what that means, right?" Hines asked the FBI agent.

"Yes," she responded.

"Crack is crack," Hines said.

Hines then returned the issue of Hunter Biden's large cash withdrawals -- over $150,000 in three months -- pushing back on the suggestion from the defense that he used the cash to pay for other things, such as Airbnb rentals.

Hines displayed bank records that showed Hunter paid for Airbnb rentals with a Visa check card.

Hines also pointed out that when Hunter Biden bought alcohol, he did so with a credit card instead of cash -- making the point that drug dealers generally favor cash transactions.