The tweet from President Donald Trump in reaction to the US Supreme Court ruling on transgender athletes in women’s sports yesterday was typically exuberant: “BIG WIN”, the president announced. “The United States Supreme Court just RULED AGAINST MEN PLAYING IN WOMEN’S SPORTS. Wow! That takes that ridiculous situation off the table!!!”
That is, of course, not quite true. The US Supreme Court did not rule against men playing in women’s sports. What it did do was confirm that individual states have the right to ban men from playing in women’s sports if they choose to do so, which is a slightly different formulation.
In the United States, which is increasingly both a country and the world’s foremost example of a misleading adjective, that likely means that transgender participation in sports will be one of those issues – like abortion in the post-Dobbs era – that divides along state lines. In progressive blue states like California and Oregon, biological males will proudly climb the top step of female sporting podiums. Across the border, in places like Idaho and Utah, they will be excluded. Absent a highly unlikely act of Congress, the law on the issue will remain the choice of individual states.
But sport does not stop neatly at state borders. That is where the ruling will have practical consequences beyond the familiar red-state, blue-state divide. College competitions, national championships and qualifying events will now have to confront the reality that an athlete eligible to compete as female in one state may be ineligible to do so in another. In practice, this means that some transgender athletes will no longer be able to use participation in women’s sport in their own state as a straightforward pathway into wider American competition.
The administrative problem is obvious: once eligibility differs from state to state, national sporting bodies must either impose their own uniform rule or accept that the category of “women’s sport” means different things in different places. That is not a situation which can be called sustainable, given the recipe for endless litigation that it creates.
Therefore, even with the caveat that yesterday's ruling was limited in scope, there are likely to be significant downstream consequences.
A Unified but Limited Ruling
Yesterday’s ruling was more unified than many might have expected. All nine justices concurred in at least part of the judgment, though the Court divided sharply on the reasoning and scope, with the three progressive justices dissenting in part. The West Virginia case involved a transgender athlete identified in court records as B.P.J.
B.P.J. is a biological male who, having transitioned as a child and having been administered puberty blockers, never underwent male puberty. Lawyers for B.P.J. argued that this meant that West Virginia’s law blocking biological males from playing in women’s sports was moot, since that law is grounded in the idea that biological masculinity imparts inherent physical advantages. Since B.P.J.’s masculinity was chemically excised from him, his lawyers argued, he therefore did not have the physical advantages of being male, and the law unfairly discriminated against him. The Court disagreed.
For Alliance Defending Freedom (ADF), whose lawyers had been involved in the litigation on behalf of female athletes defending the West Virginia and Idaho laws, the ruling was a vindication of a long-running legal strategy. ADF has argued throughout that separate teams for biological males and biological females are reasonable because “inherent physical differences between the sexes” mean that female-only competition is necessary to reduce injury risk and preserve fair competition.
That argument is echoed internationally by ADF International, whose director of UN advocacy, Giorgio Mazzoli, has said that “female sports and spaces belong to women and girls”, and that states and sports bodies must “follow the science and uphold safety and fairness in female sports”.
This is why the judgment matters beyond B.J.P. – and beyond West Virginia. The Court has not merely resolved one local dispute about one athlete. It has given legal protection to the idea that states may draw a bright line around the female category and may do so without being told by federal courts that biology itself is a form of unlawful discrimination.
Justice Kavanaugh wrote the opinion of the Court, joined by Chief Justice Roberts and Justices Thomas, Alito, Gorsuch and Barrett. The issue was framed narrowly: whether, under Title IX and the Equal Protection Clause, schools may determine eligibility for women’s and girls’ sports by biological sex. The Court’s answer was yes. It stressed that the case did not decide the separate question of whether schools may choose to allow biological males who identify as female onto girls’ or women’s teams; it decided only whether they may exclude them. This is where the greatest contrast between the judgment and the understanding of the judgment promoted by President Trump exists: the difference between the words “may” and “shall”.
A Political Question
In essence, on transgender sports, the Court has adopted the same view that it did on the matter of abortion in Dobbs: that it is a matter for individual states and institutions. Or perhaps more pertinently, that it is a matter for democratic decision and debate, rather than something governed by constitutional law.
The Court’s conservative majority has long used what is described as an “originalist” and “textualist” approach to ruling on laws: that is to say that it judges the Constitution and statutes by what the words in the documents meant at the time when they were enacted. Writing for the majority, Justice Kavanaugh made the point that when laws governing “sex” were enacted, there was no doubt in anyone’s mind as to what the word “sex” meant – it was a biological designation based on sex at birth.
However, this approach to interpreting laws does mean that future lawmakers are entirely free to make new laws, either by using words that have different meanings or by making clear in their statutory drafting what they intend their words to cover. Just as with abortion, then, the future of transgender sports participation in the United States is to be a matter for politicians, rather than judges.
The Court’s three progressive justices – Justices Kagan, Sotomayor and Jackson – arrived at broadly the same conclusion via a different route. They are much less committed to the idea that laws should be interpreted using the meaning of the words at the time they were enacted, and embrace more of a “living document” approach to legal analysis, under which the commonly understood meaning of words changes over time.
Therefore, their rejection of B.J.P.’s case was much narrower: because B.J.P.’s lawyers had conceded for the purpose of the case that “sex” did, in fact, mean “sex assigned at birth”, the progressive judges simply did not have the freedom to apply any other interpretation to the word. Had the lawyers made a different case – and argued that “sex” had a broader meaning in a world where transgender people exist – the three progressives may have had space, they indicated, to rule differently.
Taken in the round, then, the Court’s judgment is not perhaps as sweeping or as definitive as gender-critical activists might hope: it leaves open the ability of states and institutions in more progressive jurisdictions to adopt broader eligibility rules and protects only those jurisdictions within the United States that wish to maintain historic normality as it is.
An Unsettled Debate – That Benefits… the Right?
The ruling is broadly consistent with trends from the Roberts Court on these major questions which – the Obergefell ruling on gay marriage aside, where the Court imposed nationwide gay marriage by judicial ruling – broadly tend to leave disputed matters in the hands of individual states and their voters.
Politically, this may actually be helpful to the right: public polling on transgender participation in sport tends to show that an overwhelming majority of voters support keeping female sports for females only. Meanwhile, in blue states, progressive activists will push hard for Democratic politicians to enact pro-trans laws in this area. This may pose problems in the future for Democratic presidential candidates who – as Kamala Harris found out in 2024 – appear culturally out of touch. Donald Trump’s “I’m for you, Kamala is for they/them” ad in that election was one of his most potent.
Yesterday’s Court ruling means that there will be more such ads, while red states have the freedom to differentiate themselves from progressive ideology to an even greater degree.
There is also a wider sporting context. The Court’s decision comes after President Trump’s 2025 executive order, “Keeping Men Out of Women’s Sports”, which directed federal agencies to treat female sport as reserved for women and girls, and threatened federal funding for institutions that refused to comply. It also comes as international sport is moving in a similar direction. Under the new policy adopted by the International Olympic Committee ahead of the 2028 Los Angeles Games, the women’s category is to be restricted to biological women, with genetic testing used as part of the verification process.
The result is that yesterday’s ruling is not an isolated American legal event. It is part of a broader reassertion, across national and international sport, of the proposition that women’s sport exists for a reason. Some progressives will, of course, call this discriminatory and exclusionary. But the alternative is to ask women and girls to accept that their category can be entered by those who were born male, and then to call the result fairness. And that, for most voters, simply cannot stand.