After filling out the jury questionnaire, the first panel of prospective jurors are being brought into the court room one-by-one to face individual questioning from the judge and both parties. As of about 9:45 a.m. ET, the court had made it through the questioning of just six jurors.

The prospective jurors so far have include a woman who worked with the Secret Service for over two decades and whose husband was a uniformed officer in Washington, D.C., at locations including the White House.

One prospective juror who volunteered for Hilary Clinton's 2008 campaign prompted the first mention of President Joe Biden -- though not by name.

Judge Norieka asked that prospective juror if her work volunteering and donating to Democratic campaigns would prevent her from being fair in a case that involved "the son of the Democratic president of the United States."

She said it would not.

The exchange occurred as first lady Jill Biden sat in the front row of the gallery, watching intently as each juror answered their questions. The first lady is sitting next to Hunter Biden's wife, Melissa.

Earlier, a prospective juror was struck for cause because of his firm views on guns, after he told the judge he thought gun ownership was a "God-given right." He said he would not be able to be impartial in a case where someone was prevented from buying a gun due to federal law.

Hunter Biden's arrival through the front entrance of the J. Caleb Boggs Federal Building this morning means he would have passed an enormous portrait of his father, which hangs in every federal courthouse in the country.

The first batch of 50 jurors were sworn in by Judge Noreika, who instructed them not to discuss the case with anyone, including family, or to conduct any research on the case or to read any news about it.

Reporters monitoring the proceedings from the overflow room could not hear most of Noreika's statement due to technical difficulties. As technicians tried to fix the issue, they turned on a TV that happened to be playing an attack ad against Joe Biden.

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?"

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.