Since its passage 43 years ago, Title IX has proved to be a remarkably elastic law. It has been stretched and warped from its original intent to end discrimination on the basis of sex in schools that receive federal funding. As long as Title IX’s victims were wrestlers or swimmers from low-revenue men’s sports that were jettisoned to achieve participation-parity with women’s sports, nobody much cared. But now that the law is being turned into a tool to suppress free speech on college campuses, even liberals are starting to cry foul.

A tipping point was reached earlier this year when a Northwestern University film professor and feminist, Laura Kipnis, dared to criticize new Title IX regulations governing campus sex. The regulations, promulgated in the name of preventing a “hostile environment” for women, broadly defined sexual harassment as “any unwelcome conduct of a sexual nature.” An unwelcome touch or comment was grounds for a Title IX investigation, with college administers forced to be police, judge and jury in allegations of sexual harassment from offensive speech to rape.

In February Ms. Kipnis wrote in the Chronicle of Higher Education that the new rules infantilize women by encouraging them to “regard themselves as such exquisitely sensitive creatures that an errant classroom remark could impede their education.” Instead of preventing a hostile environment, she wrote, such rules instead have created an atmosphere of “sexual paranoia” that is spinning out of control. “In the post Title IX landscape,” she noted, “sexual panic rules. Slippery slopes abound.”

For her candor about the overreach of Title IX, Ms. Kipnis was hit with . . . a Title IX investigation. In an argument that would have made Joseph Stalin blush, two Northwestern students charged that Ms. Kipnis’s criticism of Title IX violated Title IX. The university launched an investigation and subjected Ms. Kipnis to what she has called an “inquisition.”

She was eventually acquitted, but the episode has left academics and the liberals who love them suddenly complaining about abuse under the law. As the liberal writer Josh Marshall declared on his Talking Points Memo blog, “The very idea that a professor could be hit with a Title IX investigation over an opinion article she wrote in The Chronicle of Higher Education is so palpably ridiculous that there is simply no need to go further.”