The deepening gender gap in American voting, with men favoring the Republican Party and women favoring the Democrats, is well known, if not well understood. So what explains the presence of millions of men in the Democratic Party and millions of women in the Republican Party? What distinguishes these two constituencies, whose partisanship runs against the grain?I asked Heather L. Ondercin, a political scientist at Appalachian State University who has written extensively on gender issues, including in “Marching to the Ballot Box: Sex and Voting in the 2020 Election Cycle,” for her thoughts on these questions. She emailed back:Regardless of identification as a man or a woman, more stereotypically “masculine” individuals (male and female) — aggressive, assertive, defends beliefs, dominant, forceful, leadership ability, independent, strong personality, willing to take a stand, and willing to take risks — tend to identify with the Republican Party. Individuals (men and women) who are more stereotypically “feminine” — affectionate, compassionate, eager to soothe hurt feelings, gentle, loves children, sensitive to the needs of others, sympathetic, tender, understanding, and warm — tend to identify with the Democratic Party.In a case study of what Ondercin describes, Melissa Deckman, a political scientist at Washington College who is also chairman of the board of the Public Religion Research Institute, and Erin Cassese, a political scientist at the University of Delaware, published research into “gendered nationalism” in 2019 that sought to identify who is most “likely to believe that American society has grown ‘too soft and feminine.’”Deckman and Cassese found a large gender gap: “56 percent of men agreed that the United States has grown too soft and feminine compared to only 34 percent of women.”But the overall gender gap paled in comparison with the gap between Democratic men and Republican men. Some 41 percent of Democratic men without college degrees agreed that American society had become too soft and feminine compared with 80 percent of Republican men without degrees, a 39-point difference. Among those with college degrees, the spread grew to 62 points: Democratic men at 9 percent, Republican men at 73 percent.The gap between Democratic and Republican women was very large, but less pronounced: 28 percent of Democratic women without degrees agreed that the country had become too soft and feminine compared with 57 percent of non-college Republican women, while 4 percent of Democratic women with degrees agreed, compared with 57 percent of college-educated Republican women.The data described by Deckman and Cassese illuminate two key aspects of contemporary American politics. First, despite the enormous gaps between men and women in their voting behavior, partisanship is far more important than gender in determining how people vote; so too is the crucial role of psychological orientation — either empathic or authoritarian, for example — in shaping allegiance to the Democratic or Republican parties.The Deckman-Cassese study is part of a large body of work that seeks to answer a basic question: Who are the men who align with the Democratic Party and who are the women who identify as Republicans?“Gender and the Authoritarian Dynamic: An Analysis of Social Identity in the Partisanship of White Americans,” a 2021 doctoral dissertation by Bradley DiMariano at the University of Missouri-St. Louis, found patterns similar to those in the Deckman-Cassese study.Among white Democratic men, an overwhelming majority, 70.7 percent, were classified in the DiMariano study as either non-authoritarian (50.71 percent) or “weak authoritarian” (19.96 percent), while less than a third, 29.3 percent, were either authoritarian (10.59 percent) or “somewhat authoritarian” (18.74 percent). In contrast, among white Republican men, less than half, 48.3 percent, were non-authoritarian or weak authoritarian, while 51.7 percent were authoritarian or somewhat authoritarian.The partisan divisions among white women were almost identical: Democratic women, 68.3 percent non- or weak authoritarian and 31.7 percent authoritarian or somewhat authoritarian; Republican women, 45.6 percent non- or weak authoritarian and 54.4 percent authoritarian or weak authoritarian.When researchers examine the stands people take on specific issues, things become more complex.Brian Schaffner, a political scientist at Tufts and a co-director of the Cooperative Election Study, provided The Times with data on levels of support and opposition on a wide range of issues for Democratic men, Democratic women, Republican men and Republican women.“One thing that strikes me is that Democratic men and women have very similar issue positions, but Republican women are consistently less conservative on the issues compared to Republican men,” Schaffner wrote by email. “Sometimes the gap between Republican men and women is actually quite large, for example on issues like equal pay, minimum wage, right to strike and prohibiting discrimination based on gender identity/sexual orientation.”Take, for example, the question of whether workers should have the right to strike. Almost identical percentages of Democratic men (84) and women (85) agreed, but Republican men and women split 42-58. Similarly, 90 percent of Democratic men and 92 percent of Democratic women support reviving Section 5 the Voting Rights Act — which was designed to prohibit discriminatory electoral practices — while 37 percent of Republican men supported that position and 56 percent of Republican women did. On legislation requiring equal pay for men and women, 93 percent of Democratic men and 97 percent of Democratic women were in support, compared with 70 percent of Republican men and 85 percent of Republican women.Natalie Jackson, director of research at P.R.R.I., provided The Times with poll data posing similar questions. Asked if “America is in danger of losing its culture and identity,” the P.R.R.I. survey found that 80 percent of Republican women and 82 percent of Republican men agreed, while 65 percent of Democratic women and 66 percent of Democratic men disagreed. Seventy-six percent of Democratic women and 77 percent of Democratic men agreed that undocumented immigrants living in this country should be allowed “to become citizens provided they meet certain requirements,” while 46 percent of Republican women and 39 percent of Republican men agreed.Conflicting attitudes toward risk also drive partisanship. In “Culture and Identity-Protective Cognition: Explaining the White Male Effect in Risk Perception,” a 2007 paper by Dan M. Kahan of Yale Law School, Donald Braman of George Washington University Law School, John Gastil of Penn State, Paul Slovic of the University of Oregon and C.K. Mertz of Decision Research, studied the attitudes toward risks posed by guns and by environmental dangers. Drawing on a survey of 1,844 Americans, their key finding was:Individuals selectively credit and dismiss asserted dangers in a manner supportive of their preferred form of social organization. This dynamic, it is hypothesized, drives the “white male effect,” which reflects the risk skepticism that hierarchical and individualistic white males display when activities integral to their cultural identities are challenged as harmful.The authors reported that conservative white Republican men (“persons who held relative hierarchical and individualistic outlooks — and particularly both simultaneously”) are the “least concerned about environmental risks and gun risks.” People “who held relatively egalitarian and communitarian views” — predominantly Democrats — “were most concerned.”On environmental risk, the people who were most risk tolerant were white men, followed by white women, then minority-group men and, the most risk averse, minority-group women. The order was slightly different in the case of risk associated with guns: White men demonstrated the least risk aversion followed by minority-group men, then white women and finally minority-group women.Kahan and his collaborators went on: “Increasing hierarchical and individualistic worldviews induce greater risk-skepticism in white males than in either white women or male or female nonwhites.”In other words, those who rank high in communitarian and egalitarian values, including liberal white men, are high in risk aversion. Among those at the opposite end of the scale — low in communitarianism and egalitarianism but high in individualism and in support for hierarchy — conservative white men are markedly more willing to tolerate risk than other constituencies.In the case of guns and gun control, the authors write:Persons of hierarchical and individualistic orientations should be expected to worry more about being rendered defenseless because of the association of guns with hierarchical social roles (hunter, protector, father) and with hierarchical and individualistic virtues (courage, honor, chivalry, self-reliance, prowess). Relatively egalitarian and communitarian respondents should worry more about gun violence because of the association of guns with patriarchy and racism and with distrust of and indifference to the well-being of strangers.A paper published in 2000, “Gender, race, and perceived risk: the ‘white male effect,’” by Melissa Finucane, a senior scientist at the RAND Corporation, Slovic, Mertz, James Flynn of Decision Research and Theresa A. Satterfield of the University of British Columbia, tested responses to 25 hazards and found that “white males’ risk perception ratings were consistently much lower” than those of white women, minority-group women and minority-group men.The white male effect, they continued “seemed to be caused by about 30 percent of the white male sample” who were “better educated, had higher household incomes, and were politically more conservative. They also held very different attitudes, characterized by trust in institutions and authorities and by anti-egalitarianism” — in other words, they tended to be Republicans.While opinions on egalitarianism and communitarianism help explain why a minority of white men are Democrats, the motivation of white women who support Republicans is less clear. Cassese and Tiffany D. Barnes, a political scientist at the University of Kentucky, address this question in their 2018 paper “Reconciling Sexism and Women’s Support for Republican Candidates: A Look at Gender, Class, and Whiteness in the 2012 and 2016 Presidential Races.”Cassese and Barnes found that in the 2016 election, social class and education played a stronger role in the voting decisions of women than of men:Among Trump voters, women were much more likely to be in the lower income category compared to men, a difference of 13 points in the full sample and 14 points for white respondents only. By contrast, the proportion of male, upper-income Trump supporters is greater than the proportion of female, upper-income Trump supporters by about 9 percentage points in the full sample and among white voters only. These findings challenge a dominant narrative surrounding the election — rather than attracting downwardly-mobile white men, Trump’s campaign disproportionately attracted and mobilized economically marginal white women.Cassese and Barnes pose the question: “Why were a majority of white women willing to tolerate Trump’s sexism?” To answer, the authors examined polling responses to three questions: “Do women demanding equality seek special favors?” “Do women complaining about discrimination cause more problems than they solve?” and “How much discrimination do women face in the United States?” Cassese and Barnes describe the first two questions as measures of “hostile sexism,” which they define as “negative views toward individuals who violate traditional gender roles.”They found that “hostile sexism” and “denial of discrimination against women are strong predictors of white women’s vote choice in 2016,” but these factors were “not predictive of voting for Romney in 2012.” Put another way, “white women who display hostile sexist attitudes and who perceive low levels of gender discrimination in society are more likely to support Trump.”In conclusion, Cassese and Barnes write:Our results also address analysts’ incorrect expectations about women voters defecting from the G.O.P. in response to Trump’s campaign. We explain this discrepancy by illustrating that some white women — particularly those without a college education — endorse hostile sexism and have weaker perceptions of systemic gender discrimination. These beliefs are associated with an increased likelihood of voting for Trump — even when controlling for partisanship and ideology.An additional variable predicting Republican partisanship is “social dominance orientation,” briefly defined as a preference for group-based hierarchy and inequality. Arnold Ho is a professor of psychology at the University of Michigan and lead author of the 2015 paper “The Nature of Social Dominance Orientation: Theorizing and Measuring Preferences for Intergroup Inequality Using the New SDO7 Scale.” He wrote that he and his colleagues found “consistent gender differences across all samples, with men having higher levels of social dominance orientation than women” and that there are “moderate to strong correlations between SDO and political conservatism across all samples, such that greater conservatism is associated with higher levels of SDO.”Ho measured conservatism on the basis of political affiliation — Democratic liberal, Republican conservative and self-identification as a social and economic liberal or conservative.A 2011 paper by I-Ching Lee of the National Taiwan University and Felicia Pratto and Blair T. Johnson of the University of Connecticut — “Intergroup Consensus/Disagreement in Support of Group-Based Hierarchy: An Examination of Socio-Structural and Psycho-Cultural Factors ” — makes the case that… in societies in which unequal groups are segregated into separate roles or living spaces, they may not compare their situations to those of other groups and may be relatively satisfied. In such cases, we would expect dominants and subordinates to be more similar in their attitude toward group-based hierarchy.On the other hand, they continued:… in societies in which people purport to value equality, subordinates may come to expect and feel entitled to equality. The evidence and signs they observe of inequality would then mean that reality is falling short of their ideal standards. This condition may lead them to reassert their opposition to group-based hierarchy and to differentiate from dominants.It may be, then, that the association of the Democratic Party with values linked more closely to women than men is a factor in the party’s loss of support among Hispanic and Black men. As my colleague Charles Blow wrote in “Democrats Continue to Struggle With Men of Color” in September: “For one thing, never underestimate the communion among men, regardless of race. Men have privileges in society, and some are drawn to policies that elevate their privileges.”President Biden’s predicament with regard to all this is reflected in the contradictory findings of a March 17-21 AP/NORC poll of 1,082 Americans on views of the Russian invasion of Ukraine.On one hand, 56 percent of those polled described Biden’s response as “not been tough enough” compared with 36 percent “about right” and 6 percent “too tough.” There were sharp partisan divisions on this question: 68 percent of Republicans said Biden’s response to the invasion was not tough enough, and 20 percent said it was about right. Fifty-three percent of Democrats said it was about right, and 43 percent said not tough enough. Independents were closer to Republicans than to Democrats: 64 percent not tough enough, 25 percent just right.Conversely, the AP/NORC survey found that 45 percent of respondents said they were very or extremely “concerned about Russia using nuclear weapons that target the United States,” 30 percent said they were “somewhat concerned,” and 25 percent said they were “not very or not at all concerned.”The potential pitfalls in the American response to the Russian invasion of Ukraine range from provoking Vladimir Putin to further escalation to diminishing the United States in the eyes of Russia and the rest of the world. The specific dangers confronting policymakers stem from serious decisions taken in a crisis climate, but the pressures on those making the decisions are tied to the competing psychological dispositions of Republicans and Democrats described above, and they are tied as well to discrepancies between men and women in toleration of the use of force.In a 2018 paper, “The Suffragist Peace,” Joslyn N. Barnhart, Allan Dafoe, Elizabeth N. Saunders and Robert F. Trager found that “At each stage of the escalatory ladder, women prefer more peaceful options.”“More telling,” the authors write,is to compare how men and women weigh the choice between backing down and conflict. Women are nearly indifferent between an unsuccessful use of force in which nothing is gained, and their country’s leader backs down after threatening force. Men, by contrast, would much rather see force used unsuccessfully than see the country’s reputation endangered through backing down. Approval among men is fully 36 percent higher for a use of force that achieves nothing and in which over 4,000 U.S. soldiers die than when the U.S. president backs down and the same objective outcome is achieved without loss of life.The gender gap on the use of force has deep roots. A 2012 study, “Men and Women’s Support for War: Accounting for the gender gap in public opinion,” found consistently higher support among men than women for military intervention in Afghanistan, Iraq and Libya, concluding that the evidence shows a “consistent ‘gender gap’ over time and across countries.” According to the study, “it would be rare to find scholarship in which gender differences on the question of using military force are not present.”The author, Ben Clements, cites “psychological differences between women and men, with the former laying greater value on group relationships and the use of cooperation and compromise, rather than aggressive means, to resolve disputes.”It should be self-evident that the last thing this country needs at a time when the world has drawn closer to the possibility of nuclear war than it has been for decades is a leader like Donald Trump, the apotheosis of aggressive, intemperate white manhood, who at the same time unreservedly seeks the admiration of Vladimir Putin and other authoritarians.The difficult task facing Biden is finding the correct balance between restraint and authority, between harm avoidance and belligerent opposition. The situation in Ukraine has the potential to damage Biden’s already weakened political stature or to provide him with an opportunity to regain some of the support he had when first elected.American wars in Vietnam, Iraq and Afghanistan have been costly for incumbent American presidents, and Biden faces an uphill struggle reversing that trend, even as the United States faces the most dangerous set of circumstances in its recent history.The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram. More