STANFORD — Last week, a Stanford swimmer was charged with raping an unconscious young woman outside a fraternity party. That same day, two Vanderbilt football players were convicted of gang-raping a classmate who also had lost consciousness before the attack.

Both cases, and many that go unreported every year, involved heavy drinking. And now some colleges — most notably, Dartmouth, which last week announced a hard-liquor ban — are looking at restricting alcohol as one way to combat rape.

But amid the growing outrage over a culture of sexual violence at America’s colleges is a debate over the role of alcohol — and whether campus crackdowns can make a difference.

Stanford already requires ID checks at parties. UC Berkeley’s Greek system banned hard alcohol from most events in 2009. Getting college students to abide by those regulations is another matter.

“I’ve never been to or heard of a party where those rules are actually followed,” said UC Berkeley student Meghan Warner, an ex-sorority member who now leads the organization Greeks Against Sexual Assault.

Warner and other advocates say linking alcohol consumption to rape is also the wrong approach because it blames intoxicated victims — suggesting they failed to protect themselves — and makes excuses for their assailants.

The implicit message is “these are nice kids that because of the demon rum behaved differently than they would otherwise,” said Lisa Maatz, of the American Association of University Women.

Research has shown that alcohol can be a factor, and that some predators use it as a tool. A decade-old study of Canadian college students published in Justice Quarterly found that men who drank at least twice a week and had friends who supported a culture of emotional and physical violence against women were nearly 10 times as likely to admit to being sexually aggressive.

“Sometimes they’ll just simply go to a party and look for the most drunk girl whose defenses are down and target her,” said John Foubert, a sexual-assault prevention activist and professor of higher education and student affairs at Oklahoma State University.

Witnesses in the rape case against 19-year-old Brock Turner paint an alcohol haze over the evening. Prosecutors say the varsity swimmer met a young woman at a Kappa Alpha fraternity party, where both were drinking. Later, cyclists passing by saw him “thrusting” on top of her and tackled him when he tried to run away, according to police reports.

Turner, who was not in a fraternity, reportedly told police that he believed the activity was consensual. The woman, who regained consciousness at a hospital hours later, told investigators that she didn’t remember walking away from the party with him or anything that followed.

After he was charged with felony rape, Turner dropped out of school and Stanford took the unusual step of immediately banning him from campus. But it is still investigating, and a spokeswoman said it is too soon to speculate about sanctions against Kappa Alpha. Fraternity members declined to comment when approached by a reporter last week.

Colleges could curb underage and binge drinking, Foubert said, but because cracking down on alcohol would likely cause such an uproar they often look the other way.

“I think students know they can get away with it, for the most part, and universities are letting them,” he said. “If universities got serious about alcohol, we would see fewer student deaths and likely fewer sexual assaults.”

Stanford’s administration says it does enforce drinking laws, as well as on-campus party regulations in effect since the 1990s. Seven students were disciplined in 2013 for alcohol-related violations, according to the university’s self-reported crime statistics — compared with just one student in the previous two years combined.

“We do actively try to hold students accountable,” said Ralph Castro, an associate dean of student affairs. But colleges everywhere have a “default drinking culture,” he said. “It’s a vexing problem.”

Last fall, Stanford adopted a stricter policy for its Greek houses: One major violation, such as a sexual assault, or three minor violations, including serving alcohol to minors, and they are stripped of on-campus housing privileges.

“The simple truth is that the broad Greek culture continues to be associated with instances of alcohol abuse, hazing and sexual misconduct,” Provost John Etchemendy wrote to Greek leaders in September. “We need a dramatic and immediate change in Greek culture, so we are taking dramatic and immediate action.”

Dartmouth, one of more than 90 colleges under federal investigation for its handling of sexual assault, last week announced new rules for a party scene made notorious by a 2012 Rolling Stone tell-all, “Confessions of an Ivy League Frat Boy.” In the piece, a former fraternity member described a pervasive culture of hazing, substance abuse and sexual assault.

Its campuswide hard-liquor ban is one of several new policies aimed to reform social life on campus and prevent rape.

But hard-alcohol restrictions at Berkeley’s fraternities appear to have done little to rein in drunkenness. ABC7 reporters investigating the rise in alcohol-related medical emergencies among UC Berkeley students in 2013 reported watching “the limp bodies of passed-out students being lugged out of frat houses.”

Still, rape-prevention advocates are encouraged by another development: Berkeley’s fraternities and sororities now require regular training on sexual consent — that consent is freely given by all involved and not just the absence of a “no.” And a 2014 state law established affirmative consent, or “yes means yes,” as the standard for colleges to use in sexual assault investigations and education.

Those efforts, more than alcohol crackdowns, are what’s important, Maatz said. “If folks can somehow let themselves believe that alcohol is the problem, then we don’t have to own up to … the rape culture that allows this kind of behavior not only to thrive but go unchecked.”

Staff writer Tracey Kaplan contributed to this story. Follow Katy Murphy at Twitter.com/katymurphy.