"With 1715 commutations in total, this undertaking was as enormous as it was unprecedented."
In his final batch of clemencies this week, Obama commuted the 35-year prison sentence of Chelsea Manning, the Army private convicted of stealing secret diplomatic and military documents and giving them to WikiLeaks, after deciding that Manning had served enough time.
He also granted a commutation to Oscar Lopez Rivera, a Puerto Rican independence activist who was a member of the Armed Forces of National Liberation (FALN), a terrorist organisation that killed and wounded people in the 1970s and 1980s with bomb attacks.
The commutation for Lopez Rivera, 74, who served 35 years in prison for a conspiracy against the US Government, had been championed by Senator Bernie Sanders, Archbishop Desmond Tutu and Hamilton songwriter Lin-Manuel Miranda.
A Texas attorney, who represented seven inmates who have received clemency from Obama over the last two years, yesterday praised him for recognising that the "criminal justice system is broken" and restoring "a sense of fairness".
"His gracious act of mercy today sealed his clemency legacy and allowed many truly deserving men and women to be reunited with their families," said Brittany Byrd.
"I was overjoyed when I received the call from Pardon Attorney Robert Zauzmer telling me the President had granted clemency to my client, Trenton Copeland, who was being buried alive under an unduly harsh sentence of life without parole for a nonviolent drug offence.
"The President saved Trenton's life today."
But, other activists expressed disappointment that Obama had not granted an early release to more deserving inmates.
"It's fantastic that the President is using his last days in office to continue to grant clemency to deserving prisoners," said Julie Stewart, founder and chairman of the board of Families Against Mandatory Minimums, which has been fighting for 18 years for clemency for drug offenders sentenced under the harsh drug laws of the 1980s and 1990s.
"But my heart aches for those who will not make the cut," Stewart said. "After over two years of believing they may have a chance for freedom, they now see that door of hope closing. I can't imagine what the pall in the prisons will feel like on January 20th when President Obama leaves office."
The Obama Administration had denied 14,485 clemency petitions and 1629 pardons, as of January 3.
One inmate who was denied clemency is 64-year-old Bruce Harrison, a decorated Vietnam War veteran who was awarded two Purple Hearts. Harrison, who is in Coleman prison in Florida, is suffering from multiple health problems and has served 23 years of a 50-year sentence for his role in transporting drugs in a government sting operation.
After Harrison and other members of his motorcycle group were sentenced, several jurors said they were dismayed to learn of the long sentence that was imposed.
"If I would have been given the right to not only judge the facts in this case, but also the law and the actions taken by the Government, the prosecutor, local and federal law enforcement officers connected in this case would be in jail and not the defendants," juror Patrick McNeil wrote afterward.
Those who championed Harrison's case contrasted it with Obama's grant of clemency to Manning, who Obama said had served "a tough sentence" after seven years in prison.
"Bruce has served 23 years, and the Government set up the entire criminal activity," said Andrea Strong, also of Families Against Mandatory Minimums.
"This is beyond disappointing. I am just heartbroken. What does he have to look forward to now? He is 64 years old. All he wanted was to come home and help raise his grandchildren. Now that dream had ended."
Former White House Counsel Kathy Ruemmler said that clemency had long been a top priority for Obama. He frequently complained to her during his first term that he was not receiving enough recommendations from the Justice Department to grant clemency.
Shortly after the 2012 election, she said, he directed her to work with the Justice Department to increase the number of clemency applications for him to consider.
"He told me to be creative and aggressive," Ruemmler said. She then worked with former Attorney General Eric Holder and Deputy Attorney General James Cole to set up a process to increase the number of clemency petitions coming from the US Pardon Attorney.
"This would not have happened organically," Ruemmler said. "This effort came directly from President Obama, and is an important part of his legacy."