AUDIE CORNISH, HOST:

One of President Obama's priorities in his final year, a criminal justice reform bill, is also one of the few issues that has some bipartisan support in Congress. But with election looming, the clock is ticking, as White House Senior Adviser Valerie Jarrett told us earlier this week.

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VALERIE JARRETT: While I think it's important to try to move forward as quickly as we can, I think, again, the fact that there is bipartisan support gives us the ability to resist some of the people who try to derail what is really an important, constructive step for us to take.

CORNISH: And while there are Republicans and Democrats who are backing criminal justice reform, include reducing mandatory minimum sentences, it's far from a sure thing. A key figure in this debate is Senator Chuck Grassley, Republican from Iowa and chairman of the Senate Judiciary Committee. Chairman Grassley, welcome to the program.

CHUCK GRASSLEY: I'm always glad to be on NPR because a lot of people listen to you, and a lot of people tell me they hear me.

CORNISH: (Laughter).

GRASSLEY: So thank you for having me.

CORNISH: Well, I want to start with this legislation. We should be clear that the Senate bill on criminal justice reform - it does not repeal mandatory minimum sentences. It makes some reductions to the length of some of those minimums. One question people have is, if, in this legislation, judges are being given little more leeway to look at the circumstances of cases, the criminal history of the defendant, why not repeal minimum sentences outright?

GRASSLEY: Well, first of all, as a practical matter, you'd never get a bill brought up. There's still a feeling of great law enforcement value in mandatory minimums because when you have mandatory minimums, then there's plea-bargaining, and when you get plea-bargaining, you can sometimes get a lot of information about a lot of people higher up the criminal chain.

And so I was faced, as chairman of the committee, with people that didn't want to do anything and then with some legitimacy or changing existing law and giving judges more leeway because our states are kind of a laboratory for our political system. And we've seen some success in states in doing this.

CORNISH: You've had colleagues in the Senate who've very much spoken out against this legislation. Senator Tom Cotton, speaking to Politico, said that it would, quote, "lead to the release of thousands of violent felons." He said it would be dangerous to proceed. How are the conversations going with colleagues who disagree with this?

GRASSLEY: I think there's a lot of misunderstanding in this bill. For instance, in regard to the senator that you quoted, I don't know that he knows that nobody could be released from prison without appearing before a judge. And the prosecutor would be there as well. And so just outright release into society is not possible under our bill.

CORNISH: This reform effort is focused on nonviolent drug offenders. Now, roughly a year ago, February 2015, you stood on the Senate floor, and you said that the myth is that there are thousands of low-level drug offenders like people smoking marijuana in federal prison for long terms, and you said these myths are often used to justify lenient and frankly dangerous sentencing proposals in this body. How has your thinking changed about this in the last year?

GRASSLEY: Well, I would say at that point, my thinking had already started to change. There's been a lot of evidence from states making some reforms that have convinced me that we ought to make an effort to get a bipartisan, bicameral, legitimate compromise, and that would maintain mandatory minimums but give an impartial person like a judge an opportunity to make a decision that somebody is ready for reentry. And I felt that we needed to pass something - if I could find a compromise, that I ought to do it as a leader of the committee.

CORNISH: So you're talking about, you know, as being chairman, just trying to find a compromise. But for you personally, do you feel any different, or do you feel like you're just trying to go along with the movement here?

GRASSLEY: Well, I wouldn't have to do this if I didn't think it was the right thing to do.

CORNISH: Do you see a sea change in the way the Republican Party thinks about this issue?

GRASSLEY: Well, that's part of my job. And one of the things that we have to do is get more Republican cosponsors. And I think that this is going to be a lot of hard work, mostly explaining to people that don't have time to read the legislation what we're trying to accomplish. But we may also have to make some compromises. And we've been working in a very congenial, bipartisan way to do it, or we wouldn't even have this bill out of committee by a 15 to 5 vote.

CORNISH: Republican Senator Chuck Grassley of Iowa - He's the chairman of the Senate Judiciary Committee. Senator Grassley, thank you so much for coming on the program.

GRASSLEY: Thank you very much. Transcript provided by NPR, Copyright NPR.