President Trump spent a large share of his final full day in office considering and issuing pardons.

His employment of clemency powers alone does not set him apart from other world leaders. But his use of pardons to shield allies and political backers from legal trouble stands out on the world stage.

Past U.S. presidents have issued politically charged pardons, but Trump’s moves have been criticized by experts and historians as unprecedented in the scale of his focus on allies, family, friends and supporters. “No former president has ever pardoned such an array of figures who are his own cronies and have been involved in crimes related to the president,” said Allan Lichtman, a professor of history at American University.

Late Tuesday, Trump granted clemency to 143 people, including former White House strategist Stephen K. Bannon, the latest in a list of former advisers and associates to receive the same treatment, along with GOP megadonor Elliott Broidy.

Executive pardons are a common power across the globe. “Just about every country has a pardon power,” said Andrew Novak, professor in the department of criminology, law and society at George Mason University and author of “Comparative Executive Clemency: The Constitutional Pardon Power and the Prerogative of Mercy in Global Perspective.” “But actual use of it varies all over the place.”

The pardon enshrined in the U.S. Constitution descends from the power held by the British crown. While the king would have given out thousands of pardons a year at the time of the American Revolution, they have grown rare in Britain. Queen Elizabeth II has used the power in the past three decades largely in posthumous cases. In 2006, she pardoned all deserters who were executed in World War I. In 2013, she pardoned the famed code breaker Alan Turing, who was prosecuted and chemically castrated in 1952 for having a same-sex relationship. Turing’s death two years after his conviction was declared a suicide.

Other former British colonies including Australia and Canada use pardons sparingly.

“In general across the Western, developed world pardons are pretty rare and that’s because there’s just other ways of providing legal mercy,” said Novak. He pointed to trends toward shorter sentences, parole and “other forms of early release.”

Novak said that most countries tend not to use the pardon for political or self-serving purposes as frequently as the U.S. presidents have been seen to, even before Trump, although Trump has pushed further than others in that direction.

Controversial pardons have punctuated modern U.S. history, including President Gerald Ford’s pardon of former president Richard M. Nixon after he was impeached, and President Bill Clinton’s pardon of billionaire fugitive Marc Rich, who was charged with tax fraud and whose ex-wife donated to Hillary Clinton’s New York senate campaign.

“I’m a little bit hard pressed to think of another system where it’s used for political patronage,” Novak said. In some countries with endemic corruption or autocratic rulers, he said, political allies might not need to be pardoned, because they would not have been convicted in the first place.

In some countries, pardons are granted in sweeping batches, in part as a means to prevent prison overcrowding.

“The King of Thailand, for instance, pardons half or a third of the prison population every year on his birthday,” Novak said. “This is because of overcrowding and because Thailand doesn’t have a Western-style parole system.”

Regular mass pardons of sometimes hundreds of prisoners at a time have occurred in Morocco, Romania, Vietnam, Zambia and Zimbabwe.

In Romania, thousands of demonstrators took to the streets in January 2017 to protest a plan to pardon thousands of prisoners. The demonstrators said the pardons would free people close to the government convicted of corruption.

A country’s use of the pardon can sometimes serve as a window into the nature of its judicial system.

“Where it’s really hard to get a retrial you’ll get more pardons,” Novak said. This could explain why the United States uses the pardon more than other Western democracies, since “we just punish more harshly than most countries.”

While pardon power can be fraught, it works as a safety valve in unique circumstances.

In 2020, approximately 6 percent of the world’s prison population was released because of the coronavirus pandemic, according to Harm Reduction International, a nongovernmental organization. The world’s overcrowded prisons proved a hotbed for the spread of the virus.

Early in the pandemic, countries took steps to initiate large acts of executive clemency.

In March, Iran announced it would temporarily free some 85,000 people in response to the virus. Turkey in April passed a bill that freed one-third of its prison population over concerns about the pandemic. Myanmar in April announced it would free nearly 25,000 prisoners, though the government said the act of clemency was not linked to the coronavirus.

This report has been updated.