Sonya Koenig is scared. A 19-year-old student from Kalamazoo, Michigan, Koenig often stays up until 2am thinking. Sometimes she paces up and down the hall, or speaks to her roommate about nightmare scenarios in which she ends up pregnant and in need of an abortion.

“Being in college, I hear stories all the time of women getting drugged at parties, or just walking down the street, and something unfortunate can happen,” says Koenig, a freshman at Michigan State University. “A guy can walk away, but [these abortion bans] mean the woman has to choose: ‘Do I want to give this baby up … or raise this child with no help from anybody?’ That’s a really hard decision.”

In August, a week after her 19th birthday, Koenig signed up to vote. She is one of many women registering in droves since the supreme court overturned the constitutional right to an abortion on 24 June.

“My brain is constantly on fire. I can’t relax. I just want this election to be over with,” says Koenig, who plans to vote to protect abortion rights in a Michigan ballot as well as voting Democrat come November.

People such as Koenig threaten to be a hugely pivotal voting bloc as the midterms loom, with organizers focusing on women and young people in voter registration drives all over the country. The first hints of that bloc’s voting power came in early August, when women in Kansas came out overwhelmingly to protect abortion rights. That election saw huge turnout, with women representing 70% of newly registered voters. They ultimately protected abortion rights in a state where Donald Trump had a 15% lead in the 2020 presidential election that he lost to Joe Biden.

That trend seems to be continuing in other states – a threat to Republican lawmakers, who in recent weeks have quietly removed abortion-related election pledges from their websites and softened their anti-abortion messaging.

For instance, the Republican gubernatorial candidate for Minnesota, Scott Jensen, had previously said he would ban abortion outright. But more recently, Jensen released a video saying he supports abortion in the cases of rape, incest, and threat to life of the pregnant person.

That pivot might not be enough to hide the party’s hardline agenda: this week, Senator Lindsey Graham of South Carolina proposed a nationwide ban on abortions after 15 weeks of pregnancy, despite months of Republican rhetoric about putting the question back to the states.

Perhaps women are unconvinced. Target Smart analyzed new voter registration from 45 states following the supreme court decision that reversed federal abortion rights – the group said female registration shot up 12%.

In Wisconsin, a battleground state that voted for Biden by a margin of just 30,000 votes in 2020, women are out-registering men by 16%. New registrants also skew hugely Democratic: 52% of newly registered voters in Wisconsin, compared to just 17% of new registrations by Republicans.

“In my 28 years of analyzing elections, I had never seen anything like what’s happened in the past two months in American politics,” Tom Bonier, chief executive of Target Smart, wrote in the New York Times. “Women are registering to vote in numbers I never witnessed before. I’ve run out of superlatives to describe how different this moment is.”

This week, the Michigan supreme court agreed to put the question of abortion rights directly to voters in November, after 730,000 Michiganders signed a petition requesting a vote. Initially, Republicans on the state’s board of canvassers tried to block the call for a referendum, complaining about spacing errors.

“I tend to do the bigger elections … I’m disabled, and standing in line for a long time is not the best for me,” says Diamond Doré, 30, from Detroit. “But seeing [the supreme court] decision, I was like, I have to vote. I’m Black and queer, and I know this means a lot of Black women are gonna die. I couldn’t stay silent.”

A grassroots activist, Doré phone canvasses, and says she has seen anti-abortion voters suddenly wanting to protect abortion. “When this happened, a lot of people sat back and said, ‘Oh, dang, this is for real. It’s not just about me, this is about tons of other women and pregnant persons around America,’” says Doré.

News of a 10-year-old girl from Ohio traveling 200 miles to Indiana to get abortion care after being raped was one thing Doré has seen sway voters. Add to that list people being forced to carry unsuccessful pregnancies to full term, at risk to their own lives, and the threat of criminalization.

“A lot of Black people feel like we are going back to what our ancestors went through,” says Doré.

William Wojciechowsk, 35, who hails from what he calls “Trump country, Michigan” (St Clair), says abortion bans across the country mean he will be voting Democrat in November for the first time.

“All the way up until the last primary election, I voted very conservatively. But I’m a transgender male, and abortions can affect me directly because I haven’t had a hysterectomy.”

Asked if he felt abandoned by his party, Wojciechowsk responded: “They’re too extreme. They’re out of their minds. These bans are putting women and trans men back into the dark ages.”

Bonier says the gender gap in voter registration seems more pronounced in some states than others.

“There’s a general sense that even though Dobbs fell, that [some of the electorate still feels] abortion is protected. In states like Oregon, where they’ve been trying to protect abortion in their state constitution, you don’t really see gender gaps [in those registering to vote] since the decision,” says Bonier. But in Republican-dominated states such as Alaska, Idaho, Kansas and Louisiana, and competitive midwestern swing states – such as Wisconsin, Pennsylvania, Ohio and Michigan – the gap is clearer, he says.

“[In those] races, governors and senators have certainly focused pretty extensively on [abortion]. And so I think voters generally have a sense of the stakes.”

Those stakes include control of Congress at a pivotal moment for American democracy – control that until recently looked like it could pass into Republican hands. The party in power has historically tended to struggle in the midterms.

“Just a few months ago, if you were to watch any of the cable news shows or read any of the political columnists, there seemed to be a universal agreement that Republicans were on their way to an inevitable wave election, where they were going to take back the Senate and take back the House. Now that doesn’t seem so sure,” Bonier says.

Now, surprise races are being won for candidates putting abortion at the centre of their campaigns. Republicans lost Alaska’s special House election at the end of August – a surprise victory for Mary Peltola, who was running against Alaska’s former governor, Sarah Palin, and against Nicholas Begich, a Republican who comes from a lineage of Alaskan Democrats.

Younger people, in particular, are playing a key role in the surge in women voting. Usually, voter turnout is particularly low for young people in midterms and primaries. But in Kansas, voters under the age of 30 comprised over 14% of ballots cast, surpassing their vote share for each of the past three general elections in Kansas.

Katharine from Minnesota, who just turned 18 and did not give her surname for privacy, will vote for the first time in November. She remembers the moment she heard about the Dobbs decision: she was sitting in history class.

“Somehow, in my mind, I still thought it wouldn’t happen, that once [the draft opinion] was leaked, maybe the public would somehow sway the decision,” she says.

She had written many school assignments about the importance of judicial precedent – and here she was seeing it all torn down.

“That’s when I knew I had to vote,” she says. “To see a lot of things I’ve grown up viewing as basic rights being taken away was very jolting.

“I am ready to put these politicians in their place. We’re tired of the older guys in office telling us what to do with our bodies.”

Bonier cautions that young people usually surge in voter registration closer to midterms, and that first-time voters make up a tiny proportion of those who are registering to vote.

But, he says, past election cycles indicate that when a group shows a greater level of intensity at a particular point – registering to vote for the first time in increased numbers – those numbers translate to a higher level of turnout overall for that group.

In Michigan, Koenig recalls feeling stirred when she heard Ruth Bader Ginsberg, one of her idols, talk about abortion as a human right, rather than simply an issue of gender.

“Forcing a woman to have a child, it affects everything,” Koenig says. “It’s not just an issue of abortion. It’s a racial issue. It’s a women’s rights issue. And I feel like a lot of these politicians are so concerned with their power, they don’t think about how we going to support babies that are going to be born.

“If something terrible happens to me, I want to have a choice in the matter.”