What did Hunter Biden do and what is a presidential pardon?

US President Joe Biden has issued a presidential pardon for his son Hunter, who was facing sentencing for two criminal cases.

The move has proven controversial, since Biden senior previously ruled out such a move. But he argued that the cases against his son were politically motivated.

His use of his pardoning powers continues a tradition of presidents on both sides of the American political divide granting clemency to people close to them.

Hunter Biden was awaiting sentencing later this month in two federal cases.

In June, he became the first child of a sitting US president to be criminally convicted - in a case relating to his gun ownership. He was found guilty by a jury in Delaware of three charges for lying about his drug use on a form when buying a handgun.

He was also awaiting sentencing after pleading guilty in September in a federal tax case that centred on whether he paid enough tax from 2016-19. The nine charges included failure to file and pay his taxes, tax evasion and filing a false return.

He faced up to 25 years in prison in the gun case and 17 years in the tax case, though he was likely to get much shorter tariffs and to serve the two sentences concurrently, experts told the New York Times.

The US Constitution decrees that a president has the broad "power to grant reprieves and pardons for offences against the United States, except in cases of impeachment".

In this case, the president's "full and unconditional pardon" covers any potential federal crimes the younger Biden may have committed from January 2014 through to December 2024.

The pardon represents legal forgiveness, ends any further punishment and restores rights such as being able to vote or run for public office.

Although the pardoning power is considered broad, it is not limitless. For example, a president can only issue pardons for federal crimes.

The issue is relevant because there is a question mark over the sentencing of Donald Trump in his hush-money case in New York. He will be unable to pardon himself in that state-level case when he returns to the White House in January.

There is a long-standing precedent of US presidents on both sides of the political divide issuing pardons - including to people close to them. This is the 26th pardon issued by Biden, a Democrat.

In 2020, Trump, a Republican, pardoned Charles Kushner, the father-in-law of his daughter Ivanka. Kushner was sentenced to two years in prison in 2004 for charges including tax evasion, campaign finance offences and witness tampering.

And in 2001, Bill Clinton, pardoned his younger half-brother, Roger Clinton, for a cocaine-related offence that dated back to 1985.

In both cases, the pardons were given to people who had already served a sentence. President Biden's intervention in his son's case comes before sentencing.

Trump granted 237 acts of clemency during his four years in the White House, according to the Pew Research Center, comprising 143 pardons and 94 commuted sentences. Many were in a flurry before he left office.

That number is significantly fewer than his predecessor Barack Obama, who during his eight-year stint granted 1,927 acts of clemency, according to Pew. These were 1,715 commutations and 212 pardons.

Trump is among those who have attacked Biden for the move, which he described as an "abuse and miscarriage of justice".

The incoming president asked whether Biden would also issue pardons to those people prosecuted over the riot on 6 January 2021 - when Trump's supporters rioted at the US Capitol building in an effort to thwart the certification of the 2020 election result.

Trump, who faced a series of legal issues while away from the White House, has repeatedly made the allegation that the US justice system has been weaponised against him and his supporters.

He has promised to issue pardons of his own for those who rioted in Washington. But who exactly will be granted clemency, and whether pardons will extend to those convicted of the most serious and violent offences, is still an open question.