Washington, United States - US presidents traditionally dole out pardons as they leave office but Joe Biden's "full and unconditional" pardon of his son Hunter is a rare instance involving a family member.
Bill Clinton granted a pardon to his half-brother Roger, who had served time in prison on 1985 drug charges, on January 20, 2001, his last day in office.
And Donald Trump pardoned Charles Kushner, a fellow real estate magnate whose son Jared is married to Trump's daughter Ivanka, at the end of his first term in the White House.
Trump, now president-elect, nominated Kushner, 70, who pleaded guilty in 2004 to tax evasion, witness tampering and making illegal campaign contributions, on Saturday to be the next US ambassador to France.
Kushner, who served 14 months in prison, admitted hiring a prostitute to seduce his brother-in-law, who was cooperating in the campaign finance inquiry, and sending a videotape of the encounter to his own sister.
Hunter Biden, who has struggled with alcohol and drug addiction, is the first child of a sitting president to receive a pardon.
His father, who leaves office on January 20, had repeatedly said he would not pardon his son -- but in announcing the move on Sunday he claimed that Hunter had been "selectively, and unfairly, prosecuted."
"I believe in the justice system, but as I have wrestled with this, I also believe raw politics has infected this process and it led to a miscarriage of justice," Biden said.
"No reasonable person who looks at the facts of Hunter's cases can reach any other conclusion than Hunter was singled out only because he is my son -- and that is wrong," the president said.
Hunter Biden pleaded guilty to tax evasion in September and was facing up to 17 years in prison. He risked 25 years in prison for the felony gun charge but was not expected to receive such stiff sentences in either case.
Presidents have also used their constitutionally-mandated pardon powers over the years on close friends and political allies.
One of the most controversial pardons in recent years was that of former president Richard Nixon by his successor in the White House, Gerald Ford.
Ford granted a "full and unconditional" pardon to Nixon, who was facing potential prosecution over the Watergate scandal, on September 8, 1974.
Trump is the first former president convicted of a crime -- falsifying business records to cover up a hush money payment to a porn star -- but he will not be able to pardon himself because the case involved state and not federal charges.
