The measure is the culmination of a long-running messaging campaign Republicans have built across the country directed at passing a “Women’s Bill of Rights.” And the GOP’s victory in Kansas may signal the success of their tactics as similar proposals get introduced or advance in Oklahoma, South Carolina, North Dakota and Tennessee.

Kansas House Republicans touted their override as a win for protecting women’s rights.

The chamber’s top lawmakers said in a statement that they “stand with women and girls in Kansas and their right to privacy, safety and dignity in single-sex spaces. Trading one group’s rights for another’s is never okay.”

Montana, where both chambers of the statehouse have cleared a bill that would also codify a definition of sex into law, is expected to join Kansas in the next few days.

“We saw they began with sports bans, but we know that the goal of the people targeting the trans community was never about sports — it was about eradicating trans people from public life,” Montana Rep. Zooey Zephyr, the first transgender woman elected to the state legislature, said in an interview.

Zephyr gained national attention this month for telling her GOP colleagues they would have blood on their hands for supporting bills that prohibit youth gender-affirming care. She was censured by the Montana state Legislature Wednesday after refusing to apologize for her remarks and hundreds of people protested her silencing at the state Capitol. The restrictions prevent her from speaking on the floor for the rest of the legislative session, though she will be able to vote remotely.

“Trans people exist,” Zephyr, a Democrat, told POLITICO. “Non-binary people exist, intersex people exist and you cannot legislate us out of existence.”

After being shut out of power in Washington, conservative women’s groups quickly turned their attention to state capitals, most of which are run by GOP majorities or supermajorities, having tested gender issues in a number of 2022 campaigns. These statehouse fights over codifying a binary definition of sex will also likely rattle school districts caught between conflicting state and federal laws that dictate which bathrooms and sports teams transgender students can access.

More than 20 states have laws restricting transgender students from playing on sports teams consistent with their gender identity, at least seven states block them from using facilities and more than 15 states bar transgender minors from accessing gender-affirming care.

The Kansas measure defines a female as someone “whose biological reproductive system is developed to produce ova.” It also specifies other terms, including “girl,” “woman,” and “mother.” A similar proposal backed by several conservative women’s groups was first introduced in May 2022 on the federal level and reintroduced this Congress in February.

“The Kansas bill would certainly be among the most restrictive ones that we’ve seen in the country — one of the most expansive, one of the most extreme and really just one of the most mean spirited and hurtful,” ACLU of Kansas Executive Director Micah Kubic said before the House vote. “School districts are probably one of the very first places where this bill and all of the other ones like it will show up.”

Republicans nationwide have been increasingly targeting transgender issues to rally their base, message on Capitol Hill and attract moderate women voters ahead of the 2024 elections.

Education Secretary Miguel Cardona was pressed by Rep. Andrew Clyde (R-Ga.) to answer “what is a woman” during an April hearing about the Education Department’s fiscal 2024 budget. Sen. Marsha Blackburn (R-Tenn.) led the same line of questioning against Ketanji Brown Jackson during her nomination for the Supreme Court last year.

And in Arkansas Gov. Sarah Huckabee Sanders’ rebuttal to President Joe Biden’s State of the Union Address, she described the president as “the first man to surrender his presidency to a woke mob that can’t even tell you what a woman is.”

House Republicans also used their slim majority to pass a bill to restrict transgender students from playing on women’s sports teams — a rebuke to the Biden administration’s Title IX athletics proposal unveiled in April.

The new rule would make categorical transgender sports bans illegal and allow transgender girls to play on girls sports teams, but with some limitations. The rule acknowledges competition levels, fairness and a school’s interest in preventing injuries especially in contact sports.

“Even if you look at Biden’s Title IX proposed rule on sports, there is a recognition that there are differences between men and women,” said May Mailman, senior legal fellow at the Independent Women’s Law Center, which has pushed for federal bills and the one in Kansas. “You can’t say women are deserving of protection, but we don’t know what women are.”

Women’s groups and conservative political leaders say the “bill of rights” laws are needed to protect sex-separated spaces like prisons and domestic violence shelters.

Lauren Bone, who served as legal director for the Women’s Liberation Front, which is backing the measures, said they are not meant to ostracize or harm people. She said there is a pressing need for definitions of sex and gender identity that people struggle to define, especially as lawmakers present legislation with the terms.

“This is codifying everybody’s definition that they already have in their head,” Bone said.

A similar bill is advancing in Montana, where the state legislature is finishing some procedural hurdles for the measure before sending it to Republican Gov. Greg Gianforte, who is expected to sign it over the objections of one of his sons who identifies as nonbinary.

Unlike Kansas’ proposal, the Montana bill is not rooted in the argument of protecting sex-separated spaces. Instead, LGBTQ advocates say the bill looks to advance and make permanent restrictions on transgender, nonbinary and intersex people that started with 2021 legislation from GOP state Sen. Carl Glimm that made it onerous for them to change their sex designation on their birth certificate. Glimm has said the bill is necessary because people conflate sex and gender.

Medical associations, including the American Academy of Pediatrics and the American Medical Association, support gender-affirming care for adolescents, which rarely, if ever, includes surgery for children. But Gianforte has pressed for legislation that would ban the use of public funds for gender-affirming care for minors, preferring they make the decision as adults.

If the state clears a binary definition of sex, the Montana ACLU said school districts and other agencies caught between conflicting state and federal laws could risk their federal funding.

“This bill would likely jeopardize $7.5 billion of federal funds — which is about half of Montana’s budget — because these definitions do not comport with federal regulations and the existing Civil Rights Act,” said Keegan Medrano, ACLU Montana’s director of policy and advocacy. “This impacts universities, schools and other elements where federal funds are currently being accessed by Montana.”

Civil rights organizations say if the legislation continues to spread across the country, transgender, nonbinary and intersex people’s existence is at risk, according to Liz King, senior education program director at the Leadership Conference on Civil and Human Rights, which represents more than 200 groups.

“There has been an effort to capitalize on fear mongering around otherness for a very long time,” King said. “And this is only the latest manifestation.”