This is the first time in American history that the child of the sitting president is going on trial. The indictment was brought by the Justice Department, specifically by David Weiss, the special counsel appointed last year to oversee the Hunter Biden probes.
Hunter Biden, 54, is accused of illegally purchasing and possessing a gun while abusing or being addicted to drugs, a violation of federal law. He pleaded not guilty to the three charges, though he has been open about his struggles with alcohol and crack cocaine addiction.
The trial could last one to two weeks and is taking place in Wilmington, Delaware.
What are the charges?
The first two charges in the three-count indictment are tied to the gun purchase itself.
When a person buys a gun, they must fill out a form with the Bureau of Alcohol, Tobacco, Firearms and Explosives and affirm that they are legally allowed to buy the weapon. Hunter Biden has been charged with lying on those forms.
These questions include: Have you been convicted of a felony? Are you a fugitive? Are you in the country unlawfully? And, importantly for this case, are you an "unlawful user of, or addicted to" illegal drugs? Hunter Biden allegedly checked the box that said, "No."
Count 3 relates to the possession of the gun. It's also against federal law to possess a gun if you are abusing drugs. Hunter Biden had the gun for 11 days in October 2018, before his girlfriend threw it in a dumpster because she was worried about his mental health, according to the indictment and texts made public in recent court filings.
"Guns present a danger if they get in the wrong hands, and that's the impetus behind these laws," Nabeel Kibria, a Washington, DC-based defense attorney who has handled hundreds of gun cases, told CNN. "The evidence seems pretty stacked against Hunter ... but who determines who is an addict? What are the bright-line rules that must be followed?"
Who are the witnesses
Prosecutors have said they plan to call about a dozen witnesses for their case.
Most notably, they've lined up testimony from three of Hunter Biden's former romantic partners to testify about his drug use around the time he bought the gun. This includes his ex-wife, Kathleen Buhle; his late brother's widow, Hallie Biden, whom Hunter Biden later dated; and Lunden Roberts, the mother of one of his children.
Their testimony could bring to life a period that Hunter Biden has described as his rock bottom, during which he was almost always on drugs or trying to get drugs. At his attempted plea hearing last year, Hunter Biden testified that he has been sober since May 2019.
"He's going to experience stress and shame at the trial," said Valerie Earnshaw, a social psychology professor at the University of Delaware who researches the stigmas surrounding addiction. "It depends on his own recovery journey, but there could be days where he experiences a lot of shame. It's a toxic emotion that eats you up. It does not motivate healthy behaviors."
Hunter Biden's lawyers wanted to call an expert who could tell the jury about how people with addictions understand their own struggles. But in a ruling Sunday, the judge blocked the defense attorneys from using that witness because of procedural defects with their disclosures to prosecutors about what the expert might say.
His team also has a forensic chemist who could testify about a white residue on his gun pouch that prosecutors say testified positive for cocaine when it was analyzed by the FBI in 2023.
Who are the prosecutors?
The case was initiated by Weiss, the former Donald Trump-appointed US attorney in Delaware. Attorney General Merrick Garland elevated Weiss to special counsel status last year, after a proposed plea deal with Hunter Biden blew up in spectacular fashion.
Hunter Biden's lawyers claimed Weiss only sought the indictment because he caved to a relentless pressure campaign from Republican lawmakers and the former president. Weiss panned this theory as a "fiction designed for a Hollywood script," and the judge overseeing the gun case concluded the allegations were "nonsensical under the facts here."
But many Republicans have criticized Weiss, claiming he offered Hunter Biden a "sweetheart deal" last year that would have resolved the gun matter and ended a tax probe with a misdemeanor-only plea. (Legal experts told CNN at the time that the proposed deal was reasonable.)
Who is the judge?
District Judge Maryellen Noreika is presiding over the case. A former patent lawyer, she had the support of Delaware's two Democratic senators when she was appointed by Trump. The Senate confirmed her nomination with a unanimous voice vote in 2018.
She oversaw last summer's dramatic hearing during which both sides asked her to approve a plea deal. But she balked and uncovered through tough questioning that there were grave differences between the parties about the scope of the deal. That hearing ended without a resolution, and the plea discussions later collapsed. That's when Garland named Weiss as special counsel.
Noreika's no-nonsense approach has kept the proceedings moving in a steady fashion. She rejected Hunter Biden's attempts to toss the case or derail the prosecution but has sided with him on several key evidentiary questions.
Could Hunter Biden go to prison?
If convicted on all three counts, the president's son could face up to 25 years in prison.
However, he doesn't have a prior criminal record, and first-time offenders often get much lower sentences than the maximum. His punishment would be solely up to Noreika.
These are federal charges, so Joe Biden has the power to pardon his son at any time. If his son is convicted, the president could also commute the sentence, sparing him from the levied punishment.
The White House has explicitly ruled out the possibility of a pardon, but that political calculus could change after the November election.
Has this ever happened before?
This is a historic moment for the United States and the history of the presidency. No president has ever tried to run the country while watching his own child go on trial.
Over the decades, there are plenty of examples of presidential family members getting in trouble. George H. W. Bush's son faced civil penalties for violating banking laws while his father was serving in the White House. Jimmy Carter's brother was scrutinized for his foreign lobbying. But nothing has sunk to the level of a criminal trial.
CNN presidential historian Douglas Brinkley said that "there's always somebody considered a black sheep in the presidential family" but that Hunter Biden's sprawling legal issues "cut unusually close to the bone because it's the president's son."
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"This trial is an albatross around President Biden's neck and weighs very heavily on his psyche," Brinkley said. "For any parent to watch their child go through addiction, and now face possible jail time, it's harrowing. You would hope that family would be his comfort zone. But in this case, family is probably his biggest worry of the moment."
The family ties have also led to some intriguing divergences between father and son.
There is a separate court battle over the constitutionality of the law that makes it illegal for drug users to own a gun. The Biden administration is defending the law and wants the Supreme Court to take up the matter. But Hunter Biden's team argued in his case - unsuccessfully - that the law violates the Second Amendment.
The jury pool
Approximately 250 Delaware residents have been summoned for jury service, according to the judge. They'll be whittled down to a panel of 12 seated jurors and four alternates.
Delaware is one of the smallest states in the country, and the Biden family looms large.
As part of the selection process - called voir dire - prospective jurors will be asked whether they can stay impartial regardless of their views about the 2024 election. They'll also be asked whether they can keep an open mind about Hunter Biden and even whether they've been eligible to vote in past elections for Joe Biden, who has held public office in Delaware since 1971.
Other questions touch on the highly politicized atmosphere surrounding the case, including, "Do you believe Hunter Biden is being prosecuted in this case because his father is the President of the United States?" or, coming from the other side, whether they think he "is not being prosecuted for other crimes because his father is the President."
What has Hunter Biden said?
Since his indictments last year, Hunter Biden hasn't said much about his legal cases.
He spoke out in December amid his fight with the House Republicans who are probing his business dealings and took responsibility for having "made mistakes in my life and wasted opportunities and privileges that I was afforded." But he slammed the "MAGA right" lawmakers who "ridiculed my struggle with addiction" and "belittled my recovery."
"They have tried to dehumanize me, all to embarrass and damage my father," he said.
Previously, Hunter Biden shared intensely personal details about his addiction in his 2021 memoir, which prosecutors plan to use against him at trial. He described his stints in rehab, his relapses, how he bought drugs near the White House, and the stretches of time when he "had no plan beyond the moment-to-moment demands of the crack pipe."
The laptop, texts and emails
One of the most notable pieces of evidence in the case will be messages from Hunter Biden's infamous laptop, which has been at the center of a yearslong political saga. Weiss said the material "is real" and will be an important part of his case, rebutting past claims from the president's son that the laptop might be fake or even Russian disinformation.
Republican officials and right-wing outlets have seized on the laptop's embarrassing emails and sexually explicit images to attack Hunter Biden, while his lawyers say the files were manipulated and sued a repair-shop owner who helped make the materials public.
Many on the right celebrated this move by Weiss, even if he hasn't verified their loftier anti-Biden allegations. The New York Post, the conservative tabloid that was first to publish messages from the laptop in 2020, recently took a victory lap on its front cover.
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In a ruling last month, Noreika said she'll let Hunter Biden challenge the authenticity of any messages introduced at trial. Some of the texts contain gut-wrenching arguments between Hunter Biden and his loved ones about his sobriety. Others show him meeting up with drug dealers, including some just a few blocks from the Wilmington federal courthouse.
"I'm a liar and a thief and a blamer and a user and I'm delusional and an addict unlike beyond and above all other addicts that you know and I've ruined every relationship I've ever cherished," he texted Hallie Biden in October 2018, according to Weiss' filings.
Prosecutors plan to use the laptop to specifically support their claim that he was using illegal drugs when he bought the gun in 2018. Weiss has not addressed - and the case is not about - Republicans' unproven allegation that emails from the laptop prove that Hunter Biden and his father were involved in corrupt foreign business deals.
What about the tax charges?
This is just one of two trials Hunter Biden faces this year.
The second case is scheduled for September in Los Angeles and revolves around Hunter Biden's troubled finances. He has pleaded not guilty to tax evasion, filing false tax returns and failing to file his taxes on time.
Originally, the trials were both scheduled for June, but Hunter Biden got a reprieve from the California federal judge, who agreed to postpone that trial. But the September trial date means that case will coincide with the final stretch of the presidential campaign.
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