Hallie Biden walked briskly to the witness box, past her brother-in-law and ex-boyfriend Hunter Biden, to chronicle a star-crossed relationship that ended in anguish, her own addiction and, eventually, his criminal prosecution.
Ms. Biden, 50, is by far the most important witness for the government. She is one of the few able to offer a detailed, and intimate, accounting of Mr. Biden’s all-consuming addiction to crack cocaine. He is on trial on charges of lying about his drug use on a form to buy a gun in October 2018, and of illegally possessing the weapon.
Moments after she sat down, prosecutors homed in on what they see as the heaviest blow to Mr. Biden’s defense, in a series of texts showing that he bought and smoked crack in the 48 hours after he purchased a gun in Delaware.
The testimony was intended to nail down a clear prosecutorial timeline, which Mr. Biden’s lawyers later undermined. But it also had the effect of forcing, Ms. Biden, a recovering addict, to revisit days of desperation and shame, so traumatic that it seemed to dim her memory. She was clearly shaken, repeatedly scanning the gallery for her new husband’s face among the crowd of gawking reporters.
“It was a terrible experience that I went through,” said Ms. Biden, a former school counselor.
“I’m embarrassed and ashamed and I regret that part of my life.”
The defendant nodded in affirmation, almost imperceptibly, as she spoke.
Ms. Biden — speaking in nervous, clipped bursts — admitted she had smoked crack after President Biden’s youngest son had introduced her to the drug in the summer of 2018, before quitting a few months later. At the time, the two were still reeling from the death of her husband and his brother, Beau Biden, from brain cancer in 2015.
The texts were wrenching. The lead prosecutor in the case, Leo J. Wise, who normally speaks with an unhurried, high-volume cadence, seemed to lower his voice and rush his delivery to read their emotionally raw, frantic conversations.
The exchanges alternated between recrimination and affection, with Ms. Biden begging him to seek treatment as he trawled the streets, often all night, for drugs.
And there were a lot of drugs. Mr. Biden, she said, bought multiple rocks of crack in Washington, where he kept an apartment — some the size of “Ping-Pong balls, or bigger maybe” — and stored them in his “backpack or car.”
Two transactions seemed to be particularly damaging to Mr. Biden’s defense, which is predicated on the assertion that he was not taking drugs around the time he signed the federal screening form to buy a Colt handgun in Wilmington on Oct. 12, 2018.
The day after, he texted Ms. Biden that he was “buying.” That indicated he was purchasing crack, she told the court.
In a second message, from late on the night of Oct. 14, Mr. Biden texted that he was “sleeping on a car” and “smoking crack” behind the minor league baseball stadium in Wilmington, after looking for a local dealer named Mookie.
It was part of a pattern of erratic behavior, she added, saying that he would be unreachable for weeks at a time and that she or her children would scrounge through his car for drugs or alcohol to help him “start anew and deal with stuff” when he reappeared exhausted at her home.
Later, under cross-examination, she said that she never personally witnessed him smoking crack in October 2018, an important admission in the view of the defense team.
Mr. Biden’s defense lawyer, Abbe Lowell, gingerly but forcefully challenged Ms. Biden’s credibility in verifying the government’s timeline, asking her several dozen questions about her specific recollections of events before and after the gun purchase.
She answered with “I don’t recall” more often than not.
“There are some things you remember, but many things you don’t,” he said.
While Mr. Lowell did not directly challenge the veracity of the texts, he suggested his client might have lied to Ms. Biden to cover up his affairs. Ms. Biden said there were times that he would tell her he was somewhere when, in fact, he was not.
On Oct. 23, 2018 — 11 days after Mr. Biden bought the gun — a panicked Ms. Biden found the weapon, drove it to a high-end supermarket in Delaware and tossed it in a trash can, hoping he would never discover who had taken it.
Soon after, he saw it was missing from his truck, spurring a series of anxious communications from Mr. Biden, who seemed to have immediately grasped the dire implications. He cursed Ms. Biden out and called her stupid, according to the texts. He told her to go back to the store and get it out of the trash can.
Prosecutors then showed surveillance video of her disposing of the gun only to return just half an hour later and frantically try to recover it.
“I realize it was a stupid idea now, but I was just so panicked,” she said on Thursday, echoing text messages she sent Mr. Biden the day she discarded it.
But before she could find the weapon, a retiree who often sifted through garbage cans looking for recyclables found the gun and supplies that had been thrown out with it and took it home. Ms. Biden called the police and filed a report.
“I’ll take the blame,” Ms. Biden told Mr. Biden. She had repeatedly urged him to go to rehab and seemed to view her actions as an intervention of sorts. “I don’t want to live like this.”
Mr. Lowell contended in his opening statement that Mr. Biden had kept the gun in a “lock box” in his truck and took it out only once in the time he owned it. But Ms. Biden claimed that he took few precautions in storing the gun.
Prosecutors produced a text from Ms. Biden chiding him for leaving it in the open console of his truck, which was unlocked and had its “windows down.” She warned Mr. Biden that “the kids search your car.”
At times, Mr. Biden’s web of romantic intrigue and obliteration of personal boundaries bordered on the comical. On Wednesday, a former girlfriend described how he regularly lost his cellphones. In October 2018, he was using a phone that used to belong to his former wife. When he texted Ms. Biden from that phone, she responded, “That freaks me out.”
He joked, “This is Kathleen and I’m gonna beat you up.” (His former wife, Kathleen Buhle, discovered her husband and Ms. Biden were having an affair before they were divorced.)
Thursday was the first time that Jill Biden, who briefly joined her husband in France to commemorate the 80th anniversary of D-Day before departing hours later, was not in the courtroom. In an interview with ABC, President Biden was asked if he would “rule out” pardoning his son. “Yes,” he replied.
David C. Weiss, the special counsel who has brought a separate case against Mr. Biden involving more serious tax offenses, has turned to the women closest to Mr. Biden to document his drug use, revisiting some of the most damaging episodes in the Biden family’s recent history as the campaign season intensifies.
On Wednesday, two of Mr. Biden’s former romantic partners, his former wife and a former girlfriend, provided vivid testimony about his addiction to crack in the weeks and months before he applied for a gun.
Almost all the events at issue in the trial happened in 2018, when Joseph R. Biden Jr. was out of office.
Mr. Biden is charged with three felonies: lying to a federally licensed gun dealer, making a false claim on the federal firearms application and possessing an illegally obtained gun. If convicted, Mr. Biden could face up to 25 years in prison and $750,000 in fines. But nonviolent first-time offenders who have not been accused of using the weapon in another crime rarely receive serious prison time for the charges.
The government’s case turns on a relatively straightforward question: whether Mr. Biden was abusing drugs when he filled out the federal firearms application claiming he was not an “unlawful user” of controlled substances.
The government has been careful not to call out Mr. Biden for his addictions, but to use details of his drug use to hold him accountable for saying he was drug-free on the form.
The sheer amount of unflattering evidence assembled by Mr. Weiss is intended to prove that Mr. Biden, knowingly lied when he claimed not to be taking drugs when he bought the handgun.
It has, in the view of even some Biden family critics, moved far beyond that goal — into a publicly humiliating trial of the president’s troubled son for an offense that, while a crime, is seldom prosecuted as a stand-alone charge for someone with no prior criminal record who has been sober for years.
But Ms. Biden, who first met Beau and Hunter Biden when they were middle schoolers in Delaware, is not just a witness in someone else’s trial.
Like Mr. Biden, she had to soldier on after the death of her husband, who was seen by everyone, particularly his father and younger brother, as the bearer of the family legacy. Her testimony took place a few days after the ninth anniversary of Beau Biden’s death.
And like her brother-in-law, she has been sober for years.
Late Thursday she appeared exhausted and struggled to follow the tangle of evidentiary threads spun by her questioners.
But she brightened when Mr. Wise — to dispel any notion she was being coached by someone in the gallery — pointed out that her new husband, whom she married just last weekend, was in the courtroom.
Mr. Wise asked: Why was he there?
“Support,” Ms. Biden said, with a grin, raising her fist.
