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.

Hunter Biden's former girlfriend Zoe Kestan testified that she saw him smoking crack as late as Sept. 20, 2018 -- a timeline that could undercut the defense's argument that he was abusing alcohol and not drugs when he purchased a gun on Oct. 12.

The defense has argued that Hunter Biden was not abusing drugs at the time of the gun purchase, after he had undergone a 12-day rehab stint in California that spanned from late August to early September. They argued repeatedly that when Hunter said in his audiobook that he "relapsed" following that rehab stay, it was only an alcohol relapse.

Kestan, however, testified that in mid-September he used crack "in the bedroom, in the bathroom."

Jurors have been laser-focused on Kestan as she testifies, some sitting up straight in their seats -- in contrast to the earlier testimony from the FBI agent who entered hundreds of text messages and audio book portions into the record, during which some jurors appeared to struggle to remain attentive.