AMNA NAWAZ: California Governor Gavin Newsom announced the largest mass commutation in the country's history, changing the state's entire death row population sentences to life in prison without parole.

The decision could grant clemency to 548 people.

Newsom, who is considering a run for the presidency, wrote in a letter to constituents that -- quote -- "State-sanctioned killing is incompatible with California's values, undermines the foundations of our legal system, and diminishes each of us."

Newsom had previously put a moratorium on executions in the state in 2019, but left hundreds on death row.

For more on all of this, I'm joined by Robin Maher, the executive director of the Death Penalty Information Center.

Welcome back, and thanks for joining us.

So, the largest such commutation in the nation's history.

We should point out, though, California has not executed anyone since 2006.

Does this decision have a real impact or is it more about sending a message?

ROBIN MAHER, Executive Director, Death Penalty Information Center: Oh, I think it does.

I mean, both historically and symbolically, this decision carries real significance.

I mean, this mass commutation will remove more than 500 people from death row.

That's 30 percent of the total number of people on death rows throughout the United States.

And Governor Newsom very publicly wrestled with this decision, taking the time to first consult with victims' family members and corrections officials, judges, lawyers, and many others.

He also looked to the research and the evidence that revealed that the death penalty in California was a very costly, deeply flawed policy choice.

And I think all of that careful work and consultation led to today's decision.

AMNA NAWAZ: And yet it's not a decision being supported by all.

Some families who lost loved ones in these crimes are not backing it, Marc Klaas among them, as I'm sure you know, the father of Polly Klaas, who was 12 years old when she was kidnapped from her home and murdered in 1993.

He told The New York Times today: "We're talking about serial killers, spree killers, cop killers, baby killers, talking about the absolute worst people in our society without a doubt.

And he's putting his energy into commuting these characters?""

The head of Crime Victims United said: "Families were asked to trust the justice system through trials, appeals, and decades of anguish.

Their loved ones deserve more than a blanket decision that sweeps aside individual judgments."

What do you say to that, Robin?

ROBIN MAHER: Right.

Well, I'm not surprised.

I am sure that some victims' family members are disappointed, just as others feel a sense of relief that these sentences are now final, and the sense of uncertainty and retraumatization that so many family members feel during these lengthy appeals is now over.

I mean, one important thing to consider is that the money, the tremendous amount of money that has been necessary to prop up the death penalty in California can now be reinvested in meaningful solutions to prevent violent crime from occurring and also to support family members who are still grieving from these terrible losses.

AMNA NAWAZ: There are some groups already talking about potentially suing Newsom to stop that.

Could this move be stalled?

ROBIN MAHER: I don't think so.

The California Constitution is very clear that Governor Newsom's authority to make these decisions is absolute and final.

There are a number of people on the row whose sentences the commutation will need to be reviewed by the California Supreme Court.

Anyone who has two felony convictions will need the court to first approve of this recommendation to commute their sentences.

But his decision regarding the other commutations is final.

AMNA NAWAZ: Robin, in the minute or so I have left, we should point out both Indiana and Florida carried out executions in their states today.

Alabama plans to do one later this evening.

And, of course, we have seen this national debate after the botched execution of Christa Pike.

When it comes to that debate, where are most Americans on this issue?

ROBIN MAHER: Well, public support for the death penalty has been declining, pretty steadily declining over the last several years.

Now barely a majority of people support use of the death penalty, and the largest number ever have very serious concerns about its reliability and its fairness.

So things have certainly changed quite a bit in the last few years.

We're expecting a new poll to be released later this month.

AMNA NAWAZ: All right, that is Robin Maher, executive director of the Death Penalty Information Center.

Robin, thank you for your time.

ROBIN MAHER: My pleasure.