Potential new members wait to enter a sorority house during spring rush near the University of Virginia campus. Andrew Harrer/Bloomberg News

Determined to reduce sexual assaults on campus, some colleges have banned frat parties, others have imposed strict new social rules and many are changing how they respond when victims come forward.

At the University of Virginia, which has been having a very public debate about its culture, a powerful national group of sororities is trying something new for this weekend: Banning its members from partying with fraternity men.

In a letter and in meetings at campus sororities, national leaders told each chapter at U-Va. that its members would not be allowed to go to any fraternity parties — for their own safety — during Boys’ Bid Night festivities Saturday, when fraternities will celebrate with new members.

When Story Hinckley, a senior from Richmond, heard the news from their chapter president, she and the  women around her were stunned: “To live in 2015 and be told that you can’t leave your house because you’re a female? I thought I was hearing it wrong, to be honest.”

It just felt, several students said, like they were back in the 1950s.

Reaction was swift, and not limited to sorority sisters. At a school full of smart, ambitious students who cherish the school’s Jeffersonian emphasis on student self-governance, it was an edict that rankled many. People called it sexist, didactic, irrational.

And at a school that has been ground zero of the campus sexual-assault debate, students who have been immersed in the issue marveled at a response that they found was so completely out of touch. At U-Va, students have studied sexual assault prevention, talked about it, changed rules (including rules about fraternity parties), advocated, taken self-defense classes, and trained themselves in ways to recognize and intervene before a situation gets out of hand.

“It’s an incredibly disproportional response to women and an incredibly antiquated understanding of safety and sexual assault,” said Abraham Axler, a second-year student who chairs the U-Va. Student Council. “We’re about 40 years past the point of ‘women are the victims and men are the aggressors.’ It’s a more complicated situation.”

The rules came ahead of a significant weekend on campus. In addition to Bid Night on Saturday, the university’s undefeated basketball team, ranked No. 2 in the nation, is hosting No. 4 Duke in what is certainly the biggest home game of the year and the biggest of the weekend nationally. (ESPN GameDay plans to be in Charlottesville for a daylong broadcast that could be followed by a night of revelry.) The idea that women would be required not to attend parties is almost unthinkable, students said.

“This was decided by national presidents who are in their mid-50s and live in Indianapolis,” Hinckley said. She told her parents about the letter and they started laughing, she said, and told her that she must have misunderstood.

But she hadn’t.

Each of the campus sorority chapters got the letter, from national leaders of member organizations of the National Panhellenic Conference — an association of sororities that regularly act in unison. But some got more-detailed directives, exceptions or warnings about repercussions. Some were told that members 21 or older could go to bars where there weren’t gatherings of fraternity brothers. Some were told that they must avoid fraternity property from Friday until 2 a.m. Sunday. (“So at 3 a.m., it’s safe?” a student asked.)

Hinckley created an online petition, saying the mandate would not help prevent rape and sexual assault but does perpetuate the idea that women are defenseless. Within 24 hours, the document had nearly 2,000 signatures. On Tuesday night, the student council voted to ask the national chapter heads to talk about it, so on Wednesday, Axler e-mailed them.

The only response by Wednesday evening was from a president who said she would be out of the country and would not be available to talk.

The overriding refrain from the council meeting, Axler said, was that this was not students fighting for their right to party. Some were upset that without any discussion, the directive seemed to be subverting all the work the campus community had put into rules designed to make fraternity parties safer. Some asked: What next? Was this just the beginning of rules to be handed down about attending social events?

Kappa Kappa Gamma declined to comment, and other national sorority chapters did not respond to requests for comment. But the National Panhellenic Conference provided a statement.

“Sorority organizations with chapters present on UVA campus, that are also NPC member organizations, collectively made the decision to not participate in men’s bid night events,” the statement says. “This directive from the sorority organizations and their inter/national presidents is intended to help uphold a NPC Unanimous Agreement of women not participating in men’s recruitment and address safety and risk management concerns associated with this tradition.”

Anthony de Bruyn, a university spokesman, said the main concern about bid night in the past was the excessive consumption of alcohol, and the school is actively working to improve safety on campus. As for this weekend, he said: “We have confidence in our students’ ability to use good judgment, be mindful of one another’s safety, and adhere to the new safety practices developed by them and outlined in the recently revised Fraternal Organization Agreements.”

Many students were sympathetic to the goals of the national sorority leaders and understood the difficulty of keeping women safe, particularly when they’re not sober. They just didn’t like the method.

“People are very agitated and very upset and see this as an obstacle to larger cultural change and a violation of free rights and student freewill,” said Ben Gorman, president of the Inter-Fraternity Council at U-Va.

Campus sexual assault has received intense scrutiny nationwide  in recent months, including from President Obama, Congress and the U.S. Department of Education, which is investigating dozens of colleges for their response to such reports.

And U-Va. became a focal point recently as it dealt with a now-discredited story of a gang rape at a fraternity that prompted the university to suspend Greek life amid a broader discussion of sexual assault. Fraternities were allowed to reopen this month after agreeing to new rules about parties and drinking that aim to increase safety.

The fraternities haven’t had a chance to prove that the new rules, designed with student input, will make their parties safer, said Erin Dyer, a third-year student from Fredericksburg, Va. Instead, the message she heard from sorority leaders was: “We’re not sure how they’re going to act, so please stay inside this night.”

“I don’t understand where or when I signed up for an organization that encouraged women to hide from men,” Dyer said.

Many women are considering quitting their chapters, several sorority sisters said. One woman said it is hard for her to feel comfortable in an organization that believes adult women “cannot look out for themselves or make their own decisions.”

It’s not just sorority sisters who were offended by the rule, Hinckley said. She feels bad for her friends who are men, too.

“Yes, I’m having to deal with this stereotype that I’m a stupid, slutty sorority girl” unable to make good decisions, she said. “They’re having to deal with the stereotype of stupid rapist fraternity brother.  ‘No women can come to your house on this night because they will all be sexually assaulted.”

Here is a copy of the letter sorority chapters received:

Letter to national sorority presidents urging non-participation in U-Va. men's bid night