AMNA NAWAZ: In the year since the Supreme Court overturn Roe v. Wade, voters in several states have shown up to overwhelmingly support abortion rights in ballot measures.

Future efforts to enshrine abortion access in state constitutions could soon face higher hurdles.

Our Laura Barron-Lopez takes a look at the battle over what appears on the ballot.

LAURA BARRON-LOPEZ: Republican legislators in multiple states have proposed measures that would make it harder for voters to change state constitutions.

That includes Ohio, where, last night, lawmakers scheduled an August special election for a resolution that would require future amendments to receive 60 percent of the vote to be adopted.

That's ahead of a pro-abortion rights effort heading to the November ballot.

A similar bill is moving through Missouri's legislature.

To discuss, I'm joined by Karen Kasler of the Ohio State House News Bureau and "NewsHour" communities reporter Gabrielle Hays, who is based in Missouri.

Ladies, thanks for joining.

Karen, I want to start with you.

Currently, Ohio requires 50 percent of the vote for ballot initiatives to be reached.

This measure would change that to 60 percent of the vote for the state Constitution to be changed.

It also requires a number of other things, like increasing the signatures from 88 counties - - excuse me -- from 44 counties to 88 counties.

Why are Republicans doing this right now and why an August special election?

KAREN KASLER, Ohio Public Radio and Television: Well, they say that they're doing this, first of all, to protect Ohio's Constitution from big money out-of-state special interests.

That's the line that we have been hearing since this discussion started.

But one of the sponsors of the House version of the resolution made it clear in a memo to his fellow Republican lawmakers that this was about possible amendments coming forward on abortion and gerrymandering, gerrymandering relating to Ohio's congressional and legislative map being ruled unconstitutionally gerrymandered last year.

This November election that reproductive rights amendment is definitely something that they're looking toward, and they want to get a vote and that 60 percent threshold in place before voters see that - - that amendment in November.

LAURA BARRON-LOPEZ: And, Gabrielle, Missouri is also pushing through a similar measure that would raise the threshold for ballot initiatives to 57 percent of the vote that would have to gain support to make it into the Constitution.

Republicans say that the state Constitution should not be malleable.

STATE REP. MIKE HENDERSON (R-MO): And I just hold the Constitution as something sacred.

I think it's a living document.

But I don't believe it should be an ever-growing document.

And Missouri's right now is an ever-growing document.

And I personally think statute is a good place to put a lot of things, but I think our Constitution is pretty sacred.

LAURA BARRON-LOPEZ: How likely is this effort going to make it onto the November ballot?

GABRIELLE HAYS: That's a good question, Laura.

I think that voters have voted on ballot measures in the last couple of years, right?

So we have seen voters use their voices to pass certain pieces of legislation or policy that did not make it through the legislature.

So, on one hand, we do have voters who maybe voted against those ballot measures that have passed in previous years.

So we're talking about marijuana, whether it was medical or recreational, among other issues.

However, there are also plenty of voters who are not very happy about this being something that the legislature is looking at.

Critics argue that it is anti-democratic, that it is taking away the people's ability to share their voices to participate in the democratic system.

And so it is not something that Missouri's voters are taking lightly.

LAURA BARRON-LOPEZ: Karen, Republicans have admitted in Ohio that this goes beyond abortion to redistricting.

Democrats in the state say that this is much bigger than that.

STATE REP. BRIDE ROSE SWEENEY (D-OH): This is not about Democrats or Republicans.

It's not just about being pro-choice or anti-abortion.

This vote is about democracy, those that respect it and those that do not.

It's about whether or not you truly want the people of Ohio to have power.

LAURA BARRON-LOPEZ: What are voters in Ohio saying about this?

KAREN KASLER: Well, it depends on which side they're on.

The number of supporters tend to be aligned with conservative groups, evangelical Christian groups, anti-abortion organizations, gun rights groups.

They say that the Constitution is -- kind of the arguments that you heard in Missouri, that it's sacred and it should be difficult to amend the Constitution.

But Democrats have been saying that this is about these big money special interests, because it's actually Republicans who have been using that big money out-of-state special interest money from a Republican billionaire from Illinois to push forward this vote.

And they said, this really takes away voters' voice, that 60 percent means that 40 percent of voters can actually dictate what's going to happen for the rest of the state.

And so they're very concerned about how this takes away essentially the voice of each person for each vote.

LAURA BARRON-LOPEZ: And are you expecting any legal challenges in Ohio, Karen?

KAREN KASLER: It's Ohio, and it's an election, so there's always the possibility of a legal challenge.

And so we are -- because in -- last month, there was a law that took effect that eliminated most August special elections.

So there -- the argument is that there had to be a law to create a new August special election for this to be voted on.

And that's not exactly what happened.

So I imagine that there probably will be litigation,because it seems like there almost always is.

LAURA BARRON-LOPEZ: Gabrielle, you mentioned that, previously, voters through a ballot initiative legalized recreational marijuana, they expanded Medicaid coverage.

I mean, does your reporting show that a majority of voters may be opposed to this initiative, this new one?

GABRIELLE HAYS: Well, I can definitely say that it seems that voters are concerned about it.

Listen, when recreational marijuana passed last year, that garnered 53 percent of the vote.

That was more than a million Missourians who voted for that, right?

These three things you mentioned, whether we're talking about recreational marijuana, like the expansion of Medicaid, medical marijuana, all of these things were passed by ballot in Michigan initiative in the recent couple of years.

And so, with that said, I mean, voters are concerned that they will not have the ability not only to participate in a democratic system, right, but also further to essentially be a check on their own General Assembly, if they feel as though they are not passing laws that they want to see past.

LAURA BARRON-LOPEZ: And, Karen, very quickly since the fall of Roe, we have seen that a number of voters have supported abortion initiatives that increase access to abortion, while Republicans are restricting access.

Are Republicans aligned with their base here?

KAREN KASLER: Oh, I think Republicans really believe that this is going to happen, but the outgoing support on this, hundreds of groups are opposed to this idea.

So there's certainly a prediction that this might not go as well as Republicans think it might.

LAURA BARRON-LOPEZ: Karen Kasler and Gabrielle Hays, thank you so much for your time.

KAREN KASLER: Great to be here.