JUDY WOODRUFF: This week, the issue of criminal justice reform, who goes to prison in America, hit a kind of critical mass, with action from President Obama, in Congress and on presidential campaigns.

As part of our Broken Justice series, our Lisa Desjardins lays out the reform movement that both Republicans and Democrats are pushing, and which some in law enforcement want to push back.

LISA DESJARDINS: It was a symbol intended to spark sweeping change, the first visit ever by a sitting U.S. president to a federal prison. President Obama's walk today through the El Reno facility outside Oklahoma City capped off his weeklong push on what he calls a broken criminal justice system.

PRESIDENT BARACK OBAMA: These are young people who made mistakes that aren't that different than the mistakes I made and the mistakes that a lot of you guys made.

LISA DESJARDINS: Monday, the president commutes sentences for 46 drug offenders. Tuesday, at the NAACP National Convention in Philadelphia, the president speaks to the racial disparity within the prison population.

PRESIDENT BARACK OBAMA: African-Americans and Latinos make up 30 percent of our population. They make up 60 percent of our inmates. About one in every 35 African-American men, one in every 88 Latino men is serving time right now. Among white men, that number is one in 214.

LISA DESJARDINS: President Obama is adding his voice to a bipartisan call for reform of the criminal justice system.

Today, Republican presidential hopeful and New Jersey Governor Chris Christie released his plan to educate prisoners.

GOV. CHRIS CHRISTIE, Republican Presidential Candidate: If we're going to incarcerate people, then we should make them do something productive, not just sit around watching TV all day. One solution is to require inmates to try and get their GED before release, so they have some minimum qualifications.

LISA DESJARDINS: Reforming criminal justice is on the radar of nearly all those who would be president. In the past few months, 18 of the current 20 presidential candidates have argued for some kind of change.

Up on Capitol Hill, ideas have made it into a group of bills that are moving toward floor votes. A House Oversight Committee hearing this week reviewed a number of reform proposals, including a bill sponsored by Senate Republican John Cornyn.

SEN. JOHN CORNYN (R), Texas: It costs $30,000 a year to incarcerate an individual in prison and less than $8,000 to keep them on pre-release custody, like home confinement and the like.

LISA DESJARDINS: Watching the hearing, Mark Holden, a lawyer for the Republican mega-donors the Koch brothers. They're also part of the movement. Koch Industries, along with Target, Home Depot and Wal-Mart, have all banned the box, or removed questions about past convictions on company job applications.

It is the latest move in decades of debate over how to stop crime.

FORMER PRESIDENT RONALD REAGAN: Today, there's a new epidemic, smokable cocaine, otherwise known as crack.

LISA DESJARDINS: The emergence of crack cocaine in the 1980s and the war on drugs led to widespread lock 'em up policies for drug offenders.

Democrats were also tough on crime. President Clinton's 1994 crime bill lengthened sentences for nonviolent criminals, while pouring nearly $10 billion into prisons. The result? The number of people behind bars skyrocketed from 500,000 in 1980 to more than 2.2 million today.

The rise in the numbers incarcerated and the drop in crime is an indicator of a working system to federal prosecutor Steve Wasserman. He fears the push for reform is shortsighted and dangerous.

STEVE WASSERMAN, Assistant U.S. Attorney: Our criminal justice system has resulted in the last 25 years in the reduction of violent crime by about 50 percent and property crime also at about 50 percent. So, crime is at its lowest levels in a generation.

LISA DESJARDINS: And you're saying it's because of criminal justice, because we incarcerate people, we put them in jail?

STEVE WASSERMAN: Incarceration does reduce crime.

LISA DESJARDINS: It is a furious debate that is now expanding in both parties. How do you continue to reduce crime, while also rethinking who is put behind bars?

For the PBS NewsHour, I am Lisa Desjardins in Washington.

GWEN IFILL: This week, Republican Senate Judiciary Chairman Chuck Grassley seemed to give the reform movement a boost, announcing he's trying to reach a compromise to lower minimum sentences and reform prisons.