AMNA NAWAZ: A new investigative report reveals the roots of a growing movement to unravel a critical election integrity tool.

The tool is called ERIC, or the Electronic Registration Information Center.

Simply, it checks voter registration rolls from participating states against databases from other agencies, like Social Security or a state DMV.

That helps states keep track of voters who have passed away or moved into or out of the state, translating into a more accurate and up-to-date list of eligible voters.

NPR's Miles Parks has covered election security for years.

He joins me now to unpack what he found and the potential impact on voter rolls across the country.

Miles, good to see you.

MILES PARKS, NPR: Yes, thanks for having me.

AMNA NAWAZ: So, this system is created to improve the accuracy of voter rolls, to help prevent voter fraud.

Do we know if it was working?

MILES PARKS: I think election officials, both Democrats and Republicans, say it was.

You know, I have been covering voting for close to six years.

I had never heard anyone criticize ERIC up until last year.

And I should note, the program in 2021 caught more than three million records that were out of date for people who had moved states.

AMNA NAWAZ: So there's evidence that it was working and support on both sides of the aisle, as you say.

MILES PARKS: Absolutely.

AMNA NAWAZ: But there were as many as some 33 member states and the District of Columbia taking part at some point.

And then an exodus of sorts began.

Your team uncovered video of one official in Louisiana, the secretary of state in January of 2022, announcing at an event Louisiana would be quitting the program.

Here's that moment.

KYLE ARDOIN (R), Louisiana Secretary of State: This week, I signed a letter, sent a letter to the Electronic Registration Information Center suspending Louisiana's participation in that program.

MAN: Yes!

(APPLAUSE) AMNA NAWAZ: Miles, it's the applause that struck me in this clip.

How did people know about this program?

Why did they care and why did they want to be out of it?

MILES PARKS: When I watched that clip, I was struck, because I thought I was the only person who knew what ERIC was.

And then you have got this roomful of people who are super passionate about it.

It's important to note, a week before that event, a far right Web site called the Gateway Pundit started writing articles about ERIC, saying, basically, it was a left-wing conspiracy to help Democrats steal elections.

None of that was true.

But it started moving towards becoming a pressure campaign over the last year, where we saw it start on this fringe far right Web site, make its way to all of these local -- like that video shows, local integrity groups that have popped up since 2020 all over the country, and found its way to state lawmakers, to state election officials, to their e-mails, to their phone calls.

We just saw this entire pressure campaign built around ERIC until clearly a number of states thought it was untenable.

AMNA NAWAZ: How did it spread so quickly?

Like, who was talking about it?

And how many more groups like that one are there out there?

MILES PARKS: Well, so our investigation centered on a key Trump ally named Cleta Mitchell.

You might remember her.

She is a very influential attorney, Republican election attorney, who now hosts a podcast about voting that she used to spread a lot of anti-ERIC misinformation.

She also runs a coalition of these sorts of grassroots groups all over the country.

And she was basically telling all these people, go to your state lawmakers, tell them to withdraw from ERIC.

And now she and a lot of the people in this world are claiming victory.

AMNA NAWAZ: So, when you look at the map, right, we mentioned there were some 33 states in the District of Columbia at some point taking part in this ERIC program.

And you see they're highlighted there, the member states at some point.

Next, we're going to show you the eight states that have since left, Iowa, Missouri, Ohio, Louisiana, West Virginia, Virginia, Florida, and Alabama, all Republican-led, we should point out.

This program works when states take part in it, right?

So what are we talking about in terms of potential impact when states leave the program?

MILES PARKS: I mean, what we're talking about is less efficient and less secure elections.

That's what every election official has told me.

That's what every election expert has told me.

So, over time, if you have slight inaccuracies in your voter rolls, it's not going to be the next day after a state pulls out, the entire election system is just going to collapse.

What it means is, over time, it can mean longer lines at precincts because they're less targeted for where people are actually living.

It can mean election mail, which can be information, it can be mail ballots, getting sent to the wrong places, which can be a security issue, as well as in inefficiency.

Taxpayer dollars are going to pay for mail that is not being received by voters.

So there's all these different downstream effects from having less accurate voter rolls.

But the election experts I talked to were just as concerned about what this says about the power of the election denial movement in this country.

We have seen this growing group of people motivated by former President Trump to push these ideas that the 2020 election was stolen.

We have not seen them get a lot of victories in terms of policy.

We haven't seen a lot of states go back to hand-counting ballots or anything, or get rid of mail voting or early voting, other things that these people want.

But this is something that they kind of planted their flag on last year, and we're seeing states respond.

AMNA NAWAZ: Is it fair to say -- and people should go to the Web site and read your full report for all the incredible reporting you have done -- these are groups that are arguing they want to prevent voter fraud.

They want to protect election integrity.

By your reporting, it seems like, by leaving this program, they're actually doing the opposite.

MILES PARKS: And that's really the common through line with a lot of the election denial movement, frankly, is pushing for policies in the name of election integrity that are actually hurting election integrity.

I mentioned hand-counting ballots is something that is a big priority for a lot of these people.

We know from research that hand-counting ballots is a much less accurate way than using machines to count them.

AMNA NAWAZ: Miles Parks, is it fair to say we will see other states leaving as well?

MILES PARKS: It's very possible.

Texas looks like they're up next.

AMNA NAWAZ: All right, we will continue to follow it all.

Miles Parks of NPR, fantastic reporting.

Thank you for joining us to talk about it.

MILES PARKS: Thanks for having me.