Hunter Biden and his wife, Melissa Cohen Biden, departing the federal courthouse in Wilmington, Del., on Friday. Haiyun Jiang for The New York Times

This week, in a courtroom in Delaware, federal prosecutors presented a sordid story of drug use and a fateful gun purchase by President Biden’s son.

The trial of Hunter Biden has laid bare some of the first family’s deepest pain, as well as the strength of the ties at its core. On Friday, Hunter’s daughter Naomi testified in his defense as the first lady, Jill Biden, who had flown back from France to be there, looked on.

The proceedings have also spurred a subtle shift in how Mr. Biden and his wife publicly approach the addiction that has shaped Hunter’s life, and as a result, their own. It’s not something either of them brings up very often — but that’s changed as it has become a key element of their son’s criminal defense.

I spoke with Katie Rogers, a White House correspondent for The New York Times who has written extensively about the Biden family and how the president is approaching this difficult moment. Our conversation was edited for length and clarify.

Hunter Biden is on trial, accused of failing to disclose his drug use on a federal application to buy a gun. It’s a remarkable moment, and a strange one, too. How did we get here?

An unmooring event was the death of Hunter’s older brother, Beau Biden, of brain cancer in 2015. Hunter, who had been struggling with alcoholism and addiction issues for a while, began using crack cocaine and started dating Beau’s widow, Hallie. In October 2018, Hunter purchased a gun, a Colt Cobra, and filled out a federal form, checking a box that affirmed that he was not addicted to or using drugs. Drug use disqualifies people from gun ownership when they buy from a licensed dealer.

As Hallie said in court yesterday, she panicked when she found the gun and threw it into a trash can behind a Delaware grocery store, where it was eventually found.

A key part of Hunter Biden’s defense is that this isn’t a crime that usually gets prosecuted. How and why did he become the target of a federal investigation into this episode?

Several weeks after the 2020 election, Hunter Biden announced that he was being investigated over his taxes and finances. The scope eventually widened to include his possession of that gun. After a plea deal fell apart last year, there was a special counsel investigation, an indictment and now this trial.

How has President Biden approached this publicly? How does he talk about Hunter, and what kind of role does Hunter play in Washington and at the White House?

They’re incredibly close, with a relationship forged in the trauma of the car crash that killed Biden’s first wife and oldest daughter — Hunter’s mother and sister. There is unflinching loyalty there, and dependence, too. Hunter lives with his wife and young son in Los Angeles, but he is often in Washington, where he stays at the White House and participates in marquee events like the Easter Egg Roll and state dinners.

When it comes to the scrutiny they face over decisions like this, the Bidens show an almost palpable defiance. The Bidens are not ashamed of Hunter, and they refuse to treat him like a liability, even though he has been the target of frequent Republican attacks that have tried to link his business dealings to his father, the president.

Hunter is somebody who has to be kept in the fold, because, as history shows, when he’s wayward, he is dangerous to himself. This is something that a lot of families can relate to, I think, and the first family, during this trial, is really acknowledging that in a way they have never done before.

Let’s talk more about that. Hunter’s addiction to crack cocaine is a central element of this trial. How has President Biden talked about that in the past — and what’s changed?

Joe Biden has often let his son try to fix things or try to stand on his own. Before his presidency, Biden spoke of addiction and alcoholism as something his older relatives or contemporaries had suffered from. He never talked about it in the context of his son, even though Hunter had been struggling for some time. It was Hunter who first detailed the extent of his problems publicly — first, in a 2019 New Yorker story, and then in his memoir. Republicans and the right-wing media had seized on his problems, trying to portray his personal life in as unflattering a light as possible.

Biden then followed suit and began to discuss addiction as a disease of the brain. At a 2021 CNN town hall, he said he was proud of his son and all that he had overcome, but basically then pointed people to his son’s book. He was still letting his son take the lead.

This week, before the trial began, Biden put out a statement saying, “A lot of families have loved ones who have overcome addiction and know what we mean.” That’s just not something he was sharing with the public before his son chose to be so public about it. The president is watching his son go to trial, making a public appeal to families across America who have loved ones who have this problem, too.

Why is it significant for the family to be acknowledging the addiction, in the context of Hunter’s defense?

That appeal dovetails with the defense’s argument, which, in part, gets into the complexity of addiction as a disease. Part of the defense’s argument is that Hunter’s sobriety in 2018 was touch and go, and there were moments he was hopeful and trying to get clean. They are trying to argue that Hunter may have been sober — or considered himself to be — when he signed the federal form. They are trying to bring a lot of nuance to this in a way the prosecution is not, and so far, prosecutors have not proven in court that Hunter was under the influence of drugs when he signed the form.

What do you know, from your reporting, about how the trial has affected President Biden and Jill Biden?

People close to the president say this is the thing he thinks about when he wakes up in the morning. He’s got Gaza, he’s got Ukraine, he’s got a re-election fight — but at the top of his mind is Hunter. He worries about his well-being. He knows his son is an addict. So this is something that weighs on him deeply, as well as on the first lady, and it ripples through the rest of the family.

The first lady’s trip back to Wilmington this week was a dramatic show of support, and another indication of where that family’s loyalties lie. The president and Hunter speak at least once a day. Those are communications meant to check in and make sure he’s OK. I assume they’re paying close attention to how the trial is going, but also, perhaps, even closer attention to how Hunter is holding up — because he has had to sit there for days and relive some of the worst moments of his life, told by the people closest to him who also went through that nightmare. And as we saw in court, they continue to suffer from his actions.