On Nov. 8, Americans may elect our first female president. While many of us are exhilarated at the idea of this feminist victory, the toll we’ve paid for coming so close to that historic barrier has been the most graphically sexist election in living memory.

What this campaign has shown us is that while feminism has transformed American culture, our politics and the lives of women, men haven’t evolved nearly as rapidly. Women changed. Too many men didn’t. What happens next?

For all of American history, white men have been both the dominant group and the default one: It was mostly white men in charge, and it was white male experiences and norms against which all others found themselves contrasted and defined. When Hillary Clinton started at Yale Law School in 1969, there was only one woman in the United States Senate. It was legal for a man to rape his wife, but abortion was mostly outlawed. Mrs. Clinton graduated as one of just 27 women in a class of 235, after being explicitly told that if accepted into law school, she would take the rightful place of a man.

Decades-long movements for women’s rights have challenged that system, breaking down the legal and social barriers that blocked women from the work force, questioning the cultural rules that so often kept women silent, and giving women more control over their bodies and, by extension, their futures. The same year Mrs. Clinton graduated from Yale, the Supreme Court held that American women had a legal right to abortion; that, coupled with expanded access to contraception, meant that women flooded into colleges and workplaces.

For women, feminism is both remarkably successful and a work in progress: We are in the work force in record numbers, but rarely ascend to the highest ranks. Sexual violence is taken more seriously than ever, but women still experience it, usually from men they know, at astounding rates. Women are more visible in public life and create more of the media and art Americans consume, but we still make up just 19 percent of Congress and 33 percent of speaking roles in the 100 top-grossing films.

Still, young women are soaring, in large part because we are coming of age in a kind of feminist sweet spot: still exhibiting many traditional feminine behaviors — being polite, cultivating meaningful connections, listening and communicating effectively — and finding that those same qualities work to our benefit in the classroom and workplace, opening up more opportunities for us to excel. And while we do find ourselves walking the tightrope between being perceived as a nice bimbo or a competent bitch, there are more ways to be a woman than ever before. It’s no longer unusual to meet a female lawyer or engineer. No one bats an eye if we cut our hair short, wear pants, pay with a credit card in our own name, win on the soccer field, or buy our own home.

Men haven’t gained nearly as much flexibility. The world has changed around them, but many have stayed stuck in the past. While women have steadily made their way into traditionally male domains, men have not crossed the other way. Men do more at home than they used to, but women still do much more — on an average day, 67 percent of men do some housework compared with 85 percent of women. Male identity remains tied up in dominance and earning potential, and when those things flag, it seems men either give up or get angry.

This, perhaps more than anything else, explains the rise of Donald J. Trump: He promised struggling white men that they could have their identities back.

There is also the simple fact that Mr. Trump is running against a woman, after eight years of our first black president. For many of the men used to seeing their own faces reflected in the halls of power, this trend away from white male authority has simply become intolerable. Today, racial animus is particularly pronounced among Trump supporters.

Mr. Trump offers dislocated white men convenient scapegoats — Mexicans, Muslims, trade policies, political correctness — and promises to return those men to their rightful place in society. With his string of model or actress wives, his beautiful pageant girls on competitive parade and his vulgar displays of wealth, Mr. Trump embodies a fantasy of masculine power reclaimed. Mrs. Clinton, an unapologetically ambitious woman running to take the place of a trailblazing, successful black man, symbolizes all the ways in which America has moved on — and in her promises to help alienated men catch up is the implicit expectation that they, too, must change.

It’s tempting to write off people who refuse to evolve, especially if their candidate loses the election. But the ugliness of the Trump campaign is evidence of how white men existing in their own shrinking universe can be a real threat. For women, greater educational achievements, a lifetime in the work force and delayed marriage and childbearing mean our lives are more expansive and outward-looking than ever before. Working-class white men, though, have seen many of their connections to society severed — unions decimated, jobs lost, families split apart or never formed at all — decreasing their social status and leaving them increasingly isolated. That many white men are struggling surely contributes to Mr. Trump’s popularity, but the driving force of this election is not money — the median household income of Trump primary voters was about $72,000 a year, $16,000 more than the national median household income. It’s power, and fury at watching it wane.

White men have always seen the world differently than women and minorities, but the norms and views of white male America are now being cast as marginal and, sometimes, delusional. This is a stunning shift.

The differences in how men and women interpret the same information is evident in responses to Mr. Trump. As of early October, more than half of men believed that Mr. Trump respected women either “some” or “a lot.” That poll was conducted after the Republican nominee was on record calling women pigs and dogs, commenting about his own daughter’s sex appeal, and labeling a former Miss Universe, Alicia Machado, “Miss Eating Machine.” At the same time, nearly two-thirds of women said that Mr. Trump didn’t respect them. While more men now agree that Mr. Trump doesn’t respect women after the vulgar “Access Hollywood” tape came to light, more than four in 10 continue to say that Mr. Trump respects us. Which really makes you wonder what these men think respecting women looks like.

The men feminism left behind pose a threat to the country as a whole. They are armed with their own facts and heaps of resentment, and one electoral loss, even a big one, will not mean widespread defeat. Other Republican candidates are no doubt observing Mr. Trump’s rabid fan base and seeing a winning strategy for smaller races in certain conservative, homogeneous locales.

In the last weeks of this ugly campaign, Mr. Trump has continued to talk about a rigged election and hint that he may not accept the results if he loses on Tuesday. While he is emboldening his followers to rage in the face of an electoral loss, Mrs. Clinton and her fellow Democrats are working to expand the ranks of women in elected office, giving the face of American power an even more extreme (and feminine) makeover. Democrats have been far better than Republicans at running diverse candidates, and if those candidates do well, the Senate could be almost a quarter female — a record high. Half of the candidates in the most competitive races to flip congressional seats from red to blue are women. Mrs. Clinton herself has reasserted her feminist identity, sometimes covertly: At both the Democratic National Convention and the final debate, she wore a crisp white suit, a sartorial homage to the white-clad suffragists whose victories are recent enough that a small number of women who were born before women could legally cast a ballot will be voting for Mrs. Clinton on Tuesday.

It’s impossible to say whether a female president would help normalize female power and heal some of the rifts made visible by this election, or if she would so enrage many men that these gaps will only cleave wider. What is clear now is that this is the great unfinished business of the feminist project, a long-fermenting suspicion brought into bright light by this election: Expanding roles and opportunities for women cannot usher in full gender equality unless men change.

Men don’t need more masculine posturing or promises to restore them to forever-gone greatness. What they need is to make their own move toward gender equality, to break down the stereotypes and fetters of masculinity. Feminists, understandably, have focused on women; we have enough to do without being tasked with improving the lot of often-misogynistic men, too. If the white men who feel ignored, disrespected and lost want to see their lives improve, they should take a cue from the great feminist strides women have made and start to embrace that progress. Life really is better with more fluid gender roles that allow individuals to do what they’re good at instead of what’s socially prescribed. Every feminist I know will tell you that men bring much more to the table than physical strength or a paycheck, and that we would love a world in which men were free to be resilient and tender, ambitious and nurturing, expressive and emotional.

Donald Trump may not agree. But women make up half the country, and since we aren’t going back in time, the same men who have long been hostile to feminism should consider coming along with us. I suspect for a lot of men, a more equal America — one with fewer cultural rules about how a man should be, and more avenues to identity and respect — would be a pretty great America to live in.