The jury began deliberations on Monday in the case of Hunter Biden, US President Joe Biden's son, who is accused of lying about his drug use when he bought a handgun in 2018.
Prosecutors have used testimony from former romantic partners, personal text messages and photos of the younger Mr Biden with drug paraphernalia to make the case that he broke the law.
“We ask you find the law applies equally to this defendant as it would to anyone else,” government prosecutor Derek Hines told the jury, as the first criminal trial of a sitting president's child reached its final phase.
The younger Mr Biden has pleaded not guilty to felony charges that include lying about his addiction when he filled out a government screening document for a Colt Cobra revolver, and illegally possessing the weapon for 11 days.
Defence lawyer Abbe Lowell compared the government's case to the work of a magician, focusing attention on addiction from months or years before the gun purchase to create the illusion that Mr Biden was a drug user when he bought it.
Over four days of testimony last week, prosecutors offered an intimate view of Mr Biden Jr’s years of struggle with alcohol and crack cocaine, which prosecutors say legally precluded him from buying a gun.
He has publicly detailed his struggle with addiction, which followed the death of his brother from brain cancer in 2015, before he became sober more than five years ago.
Mr Biden Jr's legal team sought to show that he did not consider himself an “addict” when he bought the gun and thus ticked “no” on the form that asked whether he used illegal drugs.
The trial in US District Court in Wilmington, Delaware, follows another historic first – the May 30 criminal conviction of Donald Trump, the first US president to be found guilty of a felony.
Trump is the Republican challenger to Mr Biden Sr in the November 5 presidential election.
Republicans in Congress have alleged the case and three other criminal prosecutions are politically motivated attempts to prevent Trump from regaining power.
Democrats have said, however, that the cases against him prove no one is above the law, citing the Hunter Biden prosecution as evidence that the President is not using the justice system for his own ends.
Last summer, it looked as if Mr Biden Jr would avoid prosecution in the gun case, but a deal with prosecutors was nullified after the judge, who was nominated to the bench by Trump, raised concerns about it.
The sentencing guidelines for the charges against Mr Biden Jr are 15 to 21 months, but legal experts say defendants in cases similar to his often get shorter sentences and are less likely to be incarcerated if they abide by the terms of their pre-trial release.
He also faces a trial scheduled for September on felony charges alleging he failed to pay at least $1.4 million in taxes over four years.
Mr Biden Sr said last week that he would accept the jury’s verdict and has ruled out a presidential pardon for his son.
