WASHINGTON (AP) — President Barack Obama returns to his roots at the Harvard Law Review on Thursday, penning an article about progress his administration made in reforming the criminal justice system — and the challenges that remain for the next administration.

President Barack Obama speaks during a news conference in the Brady Press Briefing Room at the White House December 16, 2016. Chip Somodevilla/Getty Images WASHINGTON (AP) — President Barack Obama returns to his roots at the Harvard Law Review on Thursday, penning an article about progress his administration made in reforming the criminal justice system — and the challenges that remain for the next administration.

His over-20,000-word commentary, "The President's Role in Advancing Criminal Justice Reform," addresses how presidents can exert influence over the criminal justice system, and how those who serve the president have a responsibility to translate that vision into practical results.

"How we treat citizens who make mistakes (even serious mistakes), pay their debt to society, and deserve a second chance reflects who we are as a people and reveals a lot about our character and commitment to our founding principles," Obama writes. "And how we police our communities and the kinds of problems we ask our criminal justice system to solve can have a profound impact on the extent of trust in law enforcement and significant implications for public safety."

In 1990, Obama was named the first black president of the Harvard Law Review. The review was founded in 1887.

Obama writes in the new article that the country cannot afford to spend $80 billion annually on incarceration, to "write off" the 70 million Americans with a criminal record, or to release 600,000 inmates each year without improving the programs that reintegrate them back into society.

"In addition, we cannot deny the legacy of racism that continues to drive inequality in how the justice system is experienced by so many Americans," he writes.

The outgoing president cautions that challenges toward true reform remain, including the passage of bipartisan criminal justice reform legislation, preventing guns from falling into the hands of those who pose a threat, and addressing the nation's opioid epidemic.

He also highlights the need for implementing "critical reforms" to forensic science and argues more technology is needed to enhance trust in and effectiveness of law enforcement.