This election cycle, as with just about every other, there is considerable handwringing about where the women voters will land. Which candidate will alienate women and which one will say just the right things? (And what do women want to hear, anyway?) Among the GOP candidates, Newt Gingrich’s woman problem has been especially chewed over; there’s the matter of his cheating and his three marriages, not to mention the condescending way he’s spoken of Michele Bachmann. Perhaps in desperation to connect with that mysterious species of voter, the Woman, the candidate’s efforts recently yielded the headline: “Gingrich Sheds Tears in Meeting with Iowa Mothers.”

But why do women vote differently than men? For decades women have been more closely aligned with the Democratic Party and men more likely to identify as Republicans. And even among a single-party electorate, there is variation between the sexes. We know from Iowa entrance polls, for instance, that Ron Paul placed third despite having much more support from male voters, whereas Rick Santorum and Mitt Romney achieved their virtual tie by winning over more women than men. As predicted, Gingrich fared poorly with women, though in fairness he faired almost as poorly with men.

The gender gap—the difference between how men and women vote—represents on average a seven point gulf between the sexes during presidential elections. Though there was evidence of some voting differences between the genders as far back as the 1960s, many political scientists date the emergence of the modern gender gap to the 1980 election, which served as the culmination of years of change in women’s lives. By then more women were working, more were single and living on their own. The women’s movement reinforced the growing sense that women’s political interests could and should be different than those of their husbands and fathers.

And then Ronald Reagan came along. According to Susan Carroll, a senior scholar at the Center for Women and Politics at Rutgers University, two of Reagan’s stances in particular alienated women. One was his hawkishness; women tend to report lower levels of support for defense spending and use of military force. The other was Reagan’s efforts to trim back the welfare state. As Carroll points out, women are more likely to be the recipients of government aid. They are more likely to be poor, more likely to be old, and more likely to be single parents. (Surprisingly, it does not appear that “women’s issues” like abortion rights or the Equal Rights Amendment were then, or are now, a major driver of the gender gap, according to political scientist Karen Kaufmann. Public opinion polls show men and women closely track one another in their views about abortion, for instance.)

So did women move away from Reagan and his party in disgust? No. Rather, women’s emerging belief in their own political entitlement permitted them to stay right where they were. “Reagan struck a chord with men, so men moved in a more Republican direction while women stayed put,” Carroll says. And in the wake of Reagan, Carroll says, the parties remained more polarized, helping to harden men and women’s party identifications. Kaufmann, of the University of Maryland, has looked at long-term election study data from 1952 to 2004 and observed that men’s support for the Democratic party declined from the mid-’70s through the eight years of Reagan’s presidency, and has remained at that lower level, with small fluctuations, ever since. In contrast, she writes, women’s voting and party identifications look about the same as they did 50 years ago.

Women’s identification with the Democrats represented something different from, say, the movement of white Southerners en masse from the Democratic to the Republican Party. Rather, the gender gap amounted to a group developing distinct electoral preferences for the first time, and is similar to what might be called the church gap. According to Ronald Brownstein, prior to the ’70s, the frequency with which a voter attended church had no bearing on who he or she voted for. But in 1972, church-goers have aligned themselves with Republicans, and they have remained there ever since.

Of course, voters still shift along the political spectrum a good bit, and when they do, men appear to move more dramatically. Studies have shown that Americans tend to act as a counterweight to the size of government. When government spends more and enacts bigger programs, Americans tend to become more conservative and to want a smaller government. When government shrinks, Americans want it bigger. Looking at social survey data going back to the 1970s, Paul Kellstedt, a political scientist at Texas A&M University, found that if women move just a little bit to the right or left, men will move many more percentage points. This asymmetrical movement causes the gender gap to expand and to shrink.

The idea that women’s political views remain relatively stable while men’s fluctuate contradicts some of our assumptions about gender. For one thing, the male voter is typically seen as the standard for the public at large, with women and other groups as viewed as mere special interests. (This is despite the fact that the majority of voters are women.) Men are representative; women are outliers. As Time magazine put it in a 1982 story on the gender gap, “Why can’t a woman vote more like a man?” This thinking may help explain our permanent election-year fascination with all those moms—Soccer Moms and Hockey Moms, Walmart Moms and Security Moms—whose identity don’t extend beyond their children, and whose beliefs and purchasing patterns are thought to offer the answer to the presidency, if only they can be riddled out.

Yet it turns out it’s the dads who are changeable. Kellstedt doesn’t know why men tend to be so much more responsive to changes in government policy. He speculates that men tend to consume more political information and may therefore be more sensitive to the news coming out of Washington. Either that or, as he likes to joke in speeches, men are just more “moody.”