On a sweltering day in Mesa, Ariz., people file into a neighbourhood church to watch a town hall with Republican vice-presidential candidate J.D. Vance. Nearby, a mega bus is splashed with a loud message: Vote "no" on Proposition 139, a ballot measure proposing to make abortion — currently banned after 15 weeks — a constitutional right in Arizona.

Barbara Miller, who lets out a cheerful "Go Trump!" as she approaches the event, likes Trump and Vance's tough talk on border security. But the registered Republican from nearby suburb Gilbert takes a more moderate tone when discussing the abortion referendum.

"I have mixed feelings about that, frankly," said Miller. "I think we're a big country with a lot of different religions, a lot of different opinions, a lot of different cultures. And I think that it's hard to have one answer for everyone."

When they cast their ballot for president in two weeks, U.S. voters in Arizona, Nevada, Colorado, Maryland, New York, Florida, Missouri, Montana, Nebraska and South Dakota will also vote on the future of abortion access in their states.

Miller's stance is a window into the complicated fight currently playing out across the country — one that no longer lends itself to tidy partisan narratives, in a post-Roe v. Wade era where abortion rights are left up to individual states.

I don't believe in all or nothing.- Barbara Miller, a voter in Gilbert, Ariz.

Party divides over abortion have widened in the past decade. At the same time, more Americans support legal abortion now than they did before the U.S. Supreme Court ruling was overturned in 2022.

That leaves supporters and opponents of election amendments, which should change individual states' policies, in a fierce tug of war to reach those who can be persuaded to vote outside traditional party lines — especially as some Republican candidates soften their stance on abortion for fear of alienating any voters.

Democratic presidential candidate Kamala Harris, meanwhile, has expressed strong support for reinstating Roe v. Wade, though some abortion activists want her to go further.

Miller, the Trump supporter, didn't say how she would vote on Proposition 139.

"I think there's compromises there," she said."I don't believe in all or nothing."

CBC News spoke with voters, experts, advocates and opponents in Arizona and Florida who shared how the fight over abortion is playing out on the ground in the run-up to the 2024 U.S. election.

Arizona's Proposition 139

During a voter education event at a community college in Mesa, volunteers with the League of Women Voters of Arizona hand out pamphlets to students passing by with information on various amendments.

The group, which has a mandate to expand and protect voters' rights, is part of a coalition supporting Proposition 139. 

"We are hearing within our own circles in the league that this transcends party," said Pinny Sheoran, the Scottsdale-based president of the group's Arizona branch.

She and other volunteers rallied earlier this year after an 1864 law that banned abortion in nearly all cases was briefly resurrected by Arizona's Supreme Court.

WATCH | How Arizona reinstated a 1864 law on abortion:

Arizona court reinstates abortion ban dating from 1864

Arizona's Supreme Court has ruled a dormant 1864 abortion law can be enforced in the state. It institutes a near-total ban on abortions, except in cases when the mother's life is in danger.

The ensuing outcry led Arizona Republican senate candidate Kari Lake to backtrack on her previous support for the law, a later line of attack during a debate with her Democratic opponent Ruben Gallego.

Trump himself — whose seesawing on abortion has threatened to alienate voters on either side of the issue — said that the law goes too far.

A lower court replaced it with the current restriction on abortion past 15 weeks, with exceptions made in cases where an abortion would save the mother's life, though not in the case of rape or incest.

That could be subject to change. A September poll showed a majority of voters in Arizona (53 per cent) said that they would vote yes on Proposition 139, just over the majority it needs to pass; 29 per cent of that group voted for Trump in 2020.

The same poll also showed that Trump was leading Harris among likely voters in Arizona (50 per cent to 45 per cent within the margin of error), though most trusted Harris more on the issue of abortion alone.

Barrett Marson, a Republican consultant based in Peoria, Ariz., said women have been mobilized to vote on the abortion amendment, including suburban women and independents who Trump and Lake have struggled with. The question is whether voters will hold a candidate's position on abortion against them.

So far, it doesn't seem like women who typically vote Republican will do so, according to Marson. 

"It appears they will vote for the initiative, but then they will also support candidates who oppose the initiative," he said.

Recent research shows that a majority of the Republican party's moderate faction believes abortion should be legal in most or all cases, while the party's conservative voters maintain that it should be mostly illegal.

Abortion advocates in Arizona have positioned the issue as a personal health issue. The opposition led by a group called It Goes Too Far, on the other hand, says anything that is less restrictive than a 15-week ban would go too far.

Speaking with registered voters in Arizona, the issue of abortion seemed to defy partisan allegiances.

Erica Price, a resident of Guadalupe, AZ., who said she is a member of Navajo Nation, described herself as pro-life. She said she isn't sure who she'll be voting for yet.

"As a Native American, the baby is alive once it is conceived," said Price. "I do believe that we should have rights, but there should be rights for the unborn as well."

Annie Lewis, a member of Republicans for Harris in Gilbert, Ariz., said she was a lifelong Republican voter primarily because of abortion rights. Now a registered independent, Lewis got emotional while discussing Proposition 139.

"While I'm not supporting late-term abortions by any means, I also think that both parties can come together in a way that's respectful to women," she said. "For me, it comes down to freedom for a woman to make her own choices."

Then there are Phoenix residents like Olivia Araiza, a pro-life Democrat who will vote against the amendment, and Silvia Sandersius, who describes herself as somewhat conservative. She plans on voting for Harris and against the abortion amendment.

"I'll vote for a donkey before I vote for Trump," said Sandersius. "I have to weigh it on the scale and he's far worse than whatever issue is out there."

Florida's Amendment 4

On the other side of the country, Florida voters are similarly engulfed by the fight over a constitutional amendment that would make it harder for the state to restrict abortion access.

Abortion is currently banned after six weeks in Florida, which critics say is before most women know they're pregnant. Earlier this year, it also became a felony to perform or actively participate in an abortion.

University of Miami student Niquelle Fleurijean said that living in a state with a six-week abortion ban is "scary."

"If me or any of my friends are in a situation where we need an abortion, and it's past the six weeks, we'd have to drive," she said. "It's a long drive out of Florida."

North Carolina is the nearest state with more accessible abortion laws. It can take up to 12 hours to drive there from Miami.

Florida had previously been an abortion refuge for women in the South, who travelled from states like Texas, Alabama and Georgia for access to the procedure.

Amendment 4, which will appear on Florida's general election ballot, states that no law can prohibit, penalize, delay or restrict abortion before fetal viability.

The bill was sponsored by a group called Floridians Protecting Freedom, and its opponents include a group that was created by Florida Gov. Ron DeSantis, who has said that the amendment's wording is too vague.

Much of the battle over abortion comes down to language. Like in Arizona, Florida's amendment proposes the fundamental right to an abortion before that viability point — meaning the point at which the fetus can survive outside the womb, generally 23 to 24 weeks into pregnancy.

Florida's amendment would provide "a constitutional right to abortion before viability or when necessary to protect the patient's health, as determined by the patient's health-care provider."

Thomas Wenski, the Archbishop of Miami, is a fierce critic of the ballot proposal. 

Florida law currently states that only a physician can terminate a pregnancy. The Archbishop claims this could change if Amendment 4 passes because of the term "health-care provider."

"I hope it doesn't," he told CBC News. "From our perspective, in which we want to honour all unborn life, we say, 'No on 4.'"

WATCH | Abortion is on the ballot in Florida this year: 

Will voters overturn Florida's strict 6-week abortion ban?

Along with casting a ballot for president this fall, Florida voters will also decide on expanding abortion rights or maintaining the state's six-week ban. CBC's Katie Simpson goes to Miami to learn more about the Amendment 4 battle and why people on both sides say the stakes couldn't be any higher.

In contrast, advocates such as Dr. Chelsea Daniels, an abortion provider at Planned Parenthood in Florida, say that the current six-week ban is designed to make doctors and patients afraid. She says that her clinic has been forced to turn away more than 700 patients since the state's ban came into effect.

"We know that this is just basic health care, and I think that when you present it to people that way, they're like, 'Yeah, it is. I do support this,'" Daniels said.

Polling released early in October suggested that Florida's Amendment 4 was falling short of the supermajority (60 per cent) that it needs to pass.

More recent polling from the University of North Florida, however, showed that it had just crossed the threshold of support from eligible voters, including more than a third of Republicans.