On January 13^th, the United States Supreme Court heard oral arguments in two cases that are, arguably, the most important of the current term.

At issue are laws passed in West Virginia and Idaho that protect female sports. According to these laws only biological females may participate in women’s sporting events.

The American Civil Liberties Union challenged both laws in court. Their attorneys contend that these laws violate the civil rights of transgender athletes who are biological males seeking to compete with women.

But, on multiple occasions, these attorneys refused to answer a basic question asked by the justices.

Here’s Justice Samuel Alito questioning Kathleen Hartnett, the attorney representing a male Boise State University cross country runner: “For equal protection purposes,” he asked, “what does it mean to be a boy or a girl or a man or a woman?”

Her answer: “We do not have a definition for the court.” Justice Alito asked a follow-up: “How can a court determine whether there’s discrimination on the basis of sex without knowing what sex means for equal protection purposes?”

Washington Post columnist Megan McArdle argues that these evasions do not help “the trans inclusion cause.” She says the Left’s contention that sex is not binary, but “a social construct, a spectrum, an incomprehensible mystery,” leads to an “obvious problem.” The case becomes “not so much an argument for trans inclusion as it is for abolishing women’s sports.”

“The law,” she writes, “requires clear definitions. Alliance Defending Freedom agrees."

In an email explaining their key role in both cases, ADF points out that “A basic understanding of the differences between men and women led to the creation of women’s sports in the first place. That same understanding led more than half of the states to pass laws protecting female athletes from having to compete against males.”

Megan McArdle says the Left’s “insistence that gender identity always trumps biology” probably means their side will lose this case.