We are about to enter the Red Zone.

That’s the period between the start of the college semester and Thanksgiving break, during which more than 50 percent of campus sexual assaults occur.

This year could be even worse than usual, as students who’ve been trapped in their parents’ houses or sequestered in their dorm rooms throughout the pandemic are finally able to intermingle.

Is there anything we can do to keep these students safe?

We could tell young women that they should drink less, dress defensively and use the buddy system.

But that message frames sexual assault as an inevitable event, like winter. Worse, it places on victims the burden of preventing assault and the blame if they don’t.

We could tell young men to be sexual only with people who clearly want to be sexual with them.

To that end, colleges around the country have been changing their sexual conduct policies to reflect the concept of affirmative consent — the presence of a “yes,” rather than the absence of a “no.” For sex to be consensual, there has to be a “yes” at every point; yeses should be strewn about like clothes on a dorm room floor. From one current college code of conduct: Consent may not be inferred from silence or passivity.”

But making it a rule doesn’t make it a reality. Despite the policy change, more than an estimated quarter of all undergraduate women will experience nonconsensual sexual contact while in college.

Partly that’s on account of actual campus predators: young men who push their targets to drink to the point of pliability, who scheme to separate them from their friends, who take sexual gratification as their due.

If you’re not one of those guys, or didn’t raise one, congratulations. My own sons are, I think, some of the good guys. They’re heading back to college this fall with respect for sexual boundaries, a supply of condoms from our bathroom cabinet and the opinion that “Baby, It’s Cold Outside” is “a little rapey.”

Unfortunately, people can think right and still act wrong.

Consider Aziz Ansari, who calls himself a feminist and created feminist television but also was called out for pressuring a woman to have sex. Or Andrew M. Cuomo, who calls himself a feminist and created feminist legislation but also sexually harassed multiple women in his orbit.

Or Austin, a young man interviewed in “Sexual Citizens,” Jennifer S. Hirsch and Shamus Khan’s recent study of campus sexual assault. Austin appears to be both generally respectful of women and unusually attentive to his girlfriend’s sexual needs. But he also realizes during his interview that he assaulted a young woman in his first week at college. After he relates a story of an awkward sexual moment, the authors ask him to reflect on it in terms of his definition of consent, and then he puts two and two together: “I guess what I did” — unwanted groping — was sexual assault. “But umm. But also, like. Yeah damn.”

“Austin knew about affirmative consent,” Hirsch and Khan write; “this didn’t stop him from doing what he did.”

The Red Zone wouldn’t exist if it were composed only of bad guys and alcohol. Even people who know better are acting within a culture that too often treats affirmative consent as a joke, teaches straight women that their first sexual priority is pleasing men (to the point of suffering pain), and presumes men are sexual aggressors and women are sexual gatekeepers. Oh — and that sex is something too private and embarrassing to talk about, with our children, with our students and even with prospective sexual partners.

Under these conditions, it’s not too hard to understand why guys who don’t think they’re bad guys commit assaults they don’t realize are assaults.

“Sexual Citizens” argues that sexual assault is, in fact, “a predictable consequence of how our society is organized.” The authors suggest ways for colleges to help — like rethinking who lives in single dorm rooms and who controls the flow of alcohol — but they also argue that by the time kids get to college, we’ve already created the conditions that make assault possible (and, at a certain time of year, even likely).

Perpetrators are to blame for their actions, but all of us are responsible for changing the culture. Even those of us who think right.

In high school, my boys were each taught in sex ed class that they should not have sex unless they were prepared to tell their parents they’d gotten a girl pregnant. This lesson, delivered just a few years ago at a good public school in New York state, ignored the entire concept of contraception, the possibility of non-heterosexual or non-penetrative sex, and the school’s responsibility to educate its students.

At the time, I laughed and shook my head, relieved that my kids knew better. Now I realize: I should have called the school to complain.