Barack Obama commuted the sentences of 153 federal inmates on Monday, the most on a single day by any US president in history.

The announcement brought the total for his presidency to more than 1,150, with the overwhelming majority issued just this year.

'We go rotten': man granted clemency describes life in the US prison system Read more

Obama also issued 78 presidential pardons, a power he has exercised much less freely during his presidency. In fact, Obama issued more pardons on Monday than he had throughout his entire eight years in office to date (70). The power to grant pardons is one historically reserved for the waning days of presidential administrations.

The latest round of commutations, which come barely a month before Obama vacates the Oval Office, are part of the Department of Justice’s Clemency 2014 initiative aimed at reducing the sentences of nonviolent federal prisoners. Since that effort began, Obama has granted clemency to more inmates than the last 11 president’s combined, including nearly 400 individuals serving life sentences.

“As the clock counts down on the Obama administration, the need for commutations of these nonviolent drug offenders – and many more like them – is more important than ever,” said Jessica Jackson Sloan, National Director of #cut50, which advocates clemency as part of an overall mission to cut the US prison population in half.

“Justice requires that the president accelerate the rate of clemencies he is granting. In the 80s and 90s, hundreds of thousands of people were handed decades-long or even life sentences behind bars for nonviolent drug offenses – but the laws have changed. These men and women would be given a shorter, more equitable, sentence if they were to be tried for the same crime today,” Jackson Sloan added.

A commutation is the shortening of a sentence, while a presidential pardon absolves a person of a crime as if they were never convicted. The supreme court has ruled that pardons carry an admission of guilt, but pardoned individuals are able to fully claim all the rights, like voting, that are denied to convicts in some jurisdictions.

Advocates of reducing the prison population through the use of clemency have been pushing Obama to release as many people as possible in the remaining days of his second term. Both President-elect Trump and Jeff Sessions, Trump’s nominee for the role of attorney general, have been critical of Obama’s use of executive power to grant clemency, even for long-serving non-violent inmates.

“The 231 individuals granted clemency today have all demonstrated that they are ready to make use – or have already made use – of a second chance,” read a statement from the White House on Monday’s historic announcement. “While each clemency recipient’s story is unique, the common thread of rehabilitation underlies all of them. For the pardon recipient, it is the story of an individual who has led a productive and law-abiding post-conviction life, including by contributing to the community in a meaningful way.”

Jackson Sloan said her hope was that with just over a month left in office, Monday’s announcement would not be Obama’s last. “President Obama has raised the hopes of thousands of families with his historic clemency initiative,” Jackson Sloan said. “We urge him not to dash those hopes by failing to process all of the applications currently awaiting his review.”

According to the Department of Justice, more than 20,000 applications have been received in the past three years.