A U.S. Supreme Court ruling affirming that states may organize school sports by athletes’ sex at birth is drawing praise from Montana conservatives, who say the decision strengthens the legal footing of a 2025 state law that restricts transgender female athletes from competing in women’s and girls’ sports.
The Court’s Decision
The Supreme Court held that states have the authority to require school sports divisions to be organized according to biological sex. Justice Brett Kavanaugh authored the majority opinion, joined by five other conservative justices. The three liberal justices dissented, with Justice Sonia Sotomayor writing the dissenting opinion.
Kavanaugh’s opinion emphasized institutional deference, writing that “the legislatures and the schools are better equipped…to assess the competing medical and scientific considerations and draw appropriate lines.” The ruling does not bar states from choosing to allow transgender athletes to participate — it simply affirms that states may prohibit it.
Montana’s HB 300
Montana’s House Bill 300, passed during the 2025 legislative session, defines it as discrimination for any public school or college to permit a student born male to compete in women’s and girls’ sports or use women’s and girls’ locker rooms. The bill cleared the legislature on a straight party-line vote, with all Republicans in favor and all Democrats opposed.
Rep. Kerri Seekins-Crowe (R-Billings), who sponsored HB 300, welcomed the Supreme Court’s ruling. “This is a good day for Montana, this is a good day for women, this is a good day for our girls growing up and participating in sports,” she said.
HB 300 has not yet faced a legal challenge, distinguishing it from its predecessor. An earlier Montana law, House Bill 112 from the 2021 session, pursued similar goals but was found unconstitutional by the Montana Supreme Court as applied to colleges and universities. Supporters of HB 300 structured the newer measure to address those legal vulnerabilities, and the Supreme Court’s ruling now provides additional federal constitutional cover.
A Broader Policy Landscape
The court’s decision arrives amid a wave of policy changes at multiple levels of government. President Donald Trump signed an executive order early in his current term directing that transgender athletes be barred from women’s and girls’ sports competitions. Both the NCAA and the U.S. Olympic and Paralympic Committees have also updated their policies governing transgender athlete participation in recent months.
Seekins-Crowe also sponsored a second measure, House Bill 121, which would require public schools, correctional facilities, public buildings, and domestic violence shelters to designate bathrooms, changing rooms, and sleeping areas by biological sex. A state judge has placed HB 121 on hold pending resolution of a lawsuit, and it remains in legal limbo.
What Comes Next
With HB 300 currently unchallenged in court, supporters of the law say the Supreme Court ruling reduces the likelihood of a successful legal attack. Whether opponents will now bring a case against HB 300 in light of the new precedent remains to be seen, though the high court’s deference to state legislatures on the underlying scientific and medical questions makes a challenge more difficult to advance under federal constitutional grounds.
The fate of HB 121, the bathroom and facilities bill, may depend in part on how lower courts interpret the scope of the Supreme Court’s ruling when that case resumes.
Montana’s political environment heading into the November 2026 general election means the transgender sports issue is likely to remain prominent. The state’s Republican-controlled legislature has made such legislation a signature priority in recent sessions, and the Supreme Court’s endorsement of state authority in this area gives those efforts a significant legal foundation going forward.
