Judge Maryellen Noreika, in her initial instructions to jurors, explained how they are to apply the law to the facts of the case for the three criminal counts Hunter Biden faces.

"You must not attach any significance to the fact that the defendant did not testify," she read aloud in the courtroom, after the defense decided not to call Hunter Biden to the stand.

The judge defined "knowingly," the central term by which jurors must determine if Hunter Biden bought the gun at the center of the case "knowing" he was an addict or user of drugs, after he stated on the gun-purchase form that he was not.

Closing arguments are scheduled to begin at 12:05 p.m. ET, after which the judge will give the jury her final instructions and their deliberations will begin.

Closing arguments will begin at about noon ET after Hunter Biden chose not to testify in his federal gun case.

The defense rested without him taking the stand, after which prosecutors presented a brief rebuttal case, then the judge gave the jury their initial instructions.

Following the prosecution's rebuttal case, the judge read the jury their initial instructions.

Court is then expected to break for lunch, with closing arguments currently scheduled for the afternoon.

The judge will then give the jury their final instructions before they begin deliberations.

The government rested its rebuttal case after a brief cross-examination of FBI special agent Erika Jensen, who testified about location and text message data relevant to the case.

Attorneys then gathered for another sidebar conference.

Attorneys for Hunter Biden, in their cross-examination of FBI Special Agent Erika Jensen, attempted to push back on prosecutors' contention that Hunter Biden was abusing drugs at the time he said on a gun-purchase form that he was drug-free.

A key piece of evidence comes from Hunter Biden's 2021 memoir, in which he described his "relapse" just weeks after leaving rehab in August -- just six weeks before purchasing the firearm.

"I stayed clean for two weeks then relapsed," Hunter Biden wrote in his book.

Defense attorney Abbe Lowell, on cross-examination, questioned the assumption that Hunter Biden's relapse implied that he was referring to his drug use -- suggesting instead that he was referring to his alcohol addiction.

"When he was referring to that in his book, was he talking about relapsing to drugs and alcohol, or do you know what he meant?" Lowell asked.

"I can only state what was stated," Jensen said.

"Which is, 'Then I relapsed?'" Lowell asked.

"Just what it says, 'I relapsed,'" Jensen replied.

Jensen also acknowledged that she could not verify that Hunter Biden was continuously using drugs from 2015 to 2019, saying, "My recollection is that there are excerpts where he was principally occupied with smoking crack cocaine. I didn't get the sense that it was the entire history."

"Meaning that there were periods of time that he was not?" Lowell asked.

"I think there -- including the period in August where we have some invoices for rehab, that there were periods where there was not," Jensen said.

It was an important moment for the defense, as Lowell managed to establish that Hunter Biden's use of drugs was not consistent -- cuing up his argument that the president's son was not on drugs at the time of his firearm purchase.

Prosecutors also entered into evidence records related to enormous cash withdrawals Hunter Biden made -- more than $150,000 from September through November of 2018, including a $5,000 withdrawal on the day he purchased the gun. Prosecutors suggested this cash was used to procure drugs; Lowell, on cross-examination, established that Hunter Biden paid $900 in cash for the weapon and accessories.

Court was subsequently recessed for the day, with Lowell's cross-examination of Jensen scheduled to resume Wednesday morning.

Prosecutors suggested that Hallie Biden would be the next witness after Jensen, making it likely that the first Biden family member to testify will take the stand at some point tomorrow.