A gun charge hanging over President Joe Biden's son, Hunter, is rarely filed by prosecutors. Will it stand up in court?
Patrick Darnell Daniels was pulled over by police in April 2022 for driving a truck without a registration plate in Hancock County, Mississippi.
Inside his vehicle officers found marijuana cigarette butts and two loaded firearms.
The 26-year-old was charged under a law that bans users of illegal drugs from owning guns.
A judge denied him bail and ruled him a flight risk, citing a previous contempt of court, a history of substance abuse and a lack of stable residence.
He was convicted and sentenced last October to nearly four years in prison.
But in August an appeals court overturned Daniels' conviction. He was freed on 26 September.
Hunter Biden, 53, faces the same charge: possession of a firearm by an unlawful user of a controlled substance. It carries a maximum prison sentence of up to five years. He is expected to plead not guilty on Tuesday.
South Texas College of Law Professor Dru Stevenson, who has published research on drug-user-gun-possession charges, says it's unusual for such cases to make it to court.
"It's just really rare that they would go after someone and prosecute them for this," Prof Stevenson said.
"But this [Hunter Biden] is a high-profile person and there's been members of Congress demanding he be prosecuted."
Of the 7,454 people sentenced for illegal gun possession in 2021, only about 5% of them were charged due to drug use, according to US Sentencing Commission data.
As well as the drug-user-gun-possession charge, Mr Biden faces two felony counts of lying about his drug addiction in a statement to a firearms dealer and on a federal form when he bought the revolver in October 2018 from a shop in Wilmington, Delaware. The twin charges are punishable by up to 10 years each.
Part of the reason the drug-user-gun-possession charge is so rare, Prof Stevenson said, is that it can be hard to prove someone is a drug user and has a gun.
The president's son, however, wrote about his addiction to crack cocaine during the period of his life when he bought the pistol in his 2021 memoir Beautiful Things.
For those who do end up charged with illegal gun possession, it's usually a "slam dunk case", Prof Stevenson said.
"If they insist on pressing charges," he said, "I don't think there's any question that [Mr Biden] will be convicted."
The president's son - who is also under investigation for allegedly failing to pay federal taxes - has remained free while his case winds its way through the courts.
The gun-and-tax charges were to be rolled in to a plea deal that would have spared Mr Biden - who has no criminal record - prison time. But that agreement collapsed in July.
Congressional Republicans - who are investigating Mr Biden's business dealings, and how much his father might have known about them, called the plea agreement a "sweetheart deal".
Mr Biden's attorneys have predicted the first criminal case against the son of a US president will never make it to trial.
They have argued that the gun charges are unconstitutional, citing a Supreme Court ruling last year - New York State Rifle & Pistol Association v Bruen.
In that decision, the justices expanded gun rights, writing that restrictions must be "consistent with this nation's historical tradition of firearm regulation".
In August the very same case was cited by the federal appeals court that overturned Patrick Darnell Daniels' conviction.
Judge Jerry Smith ruled: "At no point in the 18th or 19th Century did the government disarm individuals who used drugs or alcohol at one time from possessing guns at another."
Other cases involving the same drug-user-gun-owner prohibition - 18 USC 922 - have gone in favour of defendants after judges questioned whether the charges were constitutionally valid.
Paola Connelly was arrested in El Paso, Texas, after police responding to reports of a disturbance found firearms at her home on 28 December 2021.
Ms Connelly was charged after acknowledging to officers that she often smoked marijuana as a sleep aid and to help her anxiety.
But in April a federal judge threw out the case.
Jared Michael Harrison was pulled over for failing to stop at a red light in Lawton, Oklahoma, in May 2022.
He, too, was charged after police discovered marijuana and a loaded gun in his car.
But in February, another court dismissed that case.
Harrison's lawyer, Laura Deskin, told the OceanNewsUK: "I will say I cannot imagine Mr Harrison ever contemplated that anything in his life could possibly intersect with or impact Mr Hunter Biden.
