In 1887, Susanna Salter was a 27-year-old housewife and member of the Women’s Christian Temperance Union in Argonia, Kansas. In other words, she didn’t have much in common with the Hillary Clinton of 2016. But she was about to.

Kansas women had just won the right to vote in city elections, and the WCTU endorsed a slate of candidates for local office. Although all the recommended candidates were men, this bold act was still enough to annoy some of Argonia’s male residents, who came up with a plan to make the WCTU look silly, discredit its endorsements and, they hoped, drive the group to disband in shame. They published a fake WCTU endorsement list, exactly like the real one except that Salter was named as the group’s choice for mayor. The idea was that Salter would get only a couple of votes and the people of Argonia would see that the WCTU (and, by extension, all women) had no power in politics and no place trying to grub some up. The plan backfired spectacularly when Salter was elected, becoming the first female mayor in the U.S. and one of the first women elected to any kind of American political office.

We don’t know yet whether Hillary Clinton will be the first woman elected president of the United States. But the odds are in her favor. If it happens, being “first” isn’t the only experience she and Salter will share. Media coverage of Salter’s win was riddled with tropes that Clinton would likely find familiar (commentary on outfits, hostile gendered insults, and even insinuations that she simply didn’t have the stamina for leadership). Both women could win elections, but both also experienced rhetoric that many people today identify as sexist. It’s easy to look at these two campaigns, separated by 130 years, and wonder how much has really changed.

Political scientists will tell you that women do OK at the ballot box. “Being a woman doesn’t hurt you in an election,” said Kathleen Dolan, professor of political science at the University of Wisconsin-Milwaukee. What she means is that, when women run for political office, they win at about the same rate men do. Likewise, a candidate’s gender doesn’t seem to affect the amount of money she is able to raise for her campaign. And, should she fumble in her leadership, she isn’t judged more harshly than her male counterparts. But those rosy facts come from a body of research aimed at understanding the large gender-based disparities in American politics. With an average of 16.9 percent, the United States was 91st in female political representation at the national legislative level in 2011, behind more than 50 democratic nations. (It hasn’t gotten particularly better since.) Being a woman may not hurt you in an election, but it definitely seems to have an impact on the process of getting to that election — largely because women themselves are reluctant to run. And there’s reason to believe that reluctance could have a lot to do with how some women who do run experience a sort of sexism that scientific research isn’t really documenting.

Theoretically, women shouldn’t do as well as they do in elections. Numerous findings from sociological research suggest that a female politician is likely to be at a disadvantage because she is female. For instance, research shows that Americans think of certain traits as being part and parcel with good leadership — assertiveness, ambition, toughness, self-confidence — and these traits also correlate strongly with our gendered expectations for masculine behavior. They’re almost the opposite of what we expect from women. Given that we also know that women who deviate from gender stereotypes are punished for it, it was long assumed that female politicians would suffer in the polls simply because the mere act of running for office meant they weren’t being “feminine” enough, said Monica Schneider, associate professor of political science at Miami University.

But experimental research and analysis of actual elections have failed to find any evidence of this. Instead, over and over, Schneider told me, studies have found that, while Americans hold gender stereotypes about women’s traits and they hold gendered ideas about certain political issues, neither of those things seems to affect the way people vote. “On the whole, sexism doesn’t have a huge impact on whether women get elected,” she told me. Instead, political party is the primary factor people consider when voting, followed by incumbency.

But that doesn’t mean there is no sexism, said Schneider, Dolan, and other political scientists. And it doesn’t mean sexism isn’t having an impact on elections. Instead, sexism may be inconsistently affecting women who run for political office, depending on factors such as which job a specific woman is running for, what’s happening in the world when she runs, and her personality and history. In current U.S. society, sexism doesn’t often take the form of a mustachioed villain cackling about his refusal to vote for any woman ever. It’s more likely to play out in nuanced and complex ways. And those nuances are difficult for the current science to capture.

For instance, knowing that party affiliation is the primary factor that voters consider and that it seems to override gendered biases that otherwise exist, you might wonder how female candidates fare in primary elections. But that issue really hasn’t been studied very much, Dolan and others told me. One paper suggests that sexism and gender biases might matter more at this level but still depend on the year and the party. From 1994 to 2012, Republican women in U.S. House of Representatives primary races have consistently fared worse than Democratic women in their primaries.

Media representation is another good example of how research might not be capturing all the nuances of sexism in politics. Although research shows that female candidates now get the same amount of coverage as male candidates, the focus of that coverage seems to be different. In 2008, for instance, media coverage of GOP vice presidential nominee Sarah Palin was more likely to focus on gender, appearance and family status than the coverage of Democratic vice presidential nominee Joe Biden. And these studies on media representation don’t include informal media, such as what voters see on Twitter and Facebook or on T-shirts sold at campaign events. In other words, “Trump that bitch” isn’t captured in this data. Nor was the time comedian Andy Richter took to Twitter to explain that Republican Rep. Michele Bachmann could be “cured” by sex. And no one I spoke with knew of any studies looking at what, if any, impact overall sexism and this kind of rhetoric have on female candidates before and after they’re in office.

It’s also worth noting that all this data is affected by small sample sizes, by the fact that it’s mostly coming from lower-level races and by the fact that there have been more female Democratic candidates than Republicans. Think about research on women running for the presidency. Not only is the sample size of all candidates tiny, Hillary Clinton is really an N of 1 when it comes to female candidates running in the general election with a mainstream party.

The 2016 presidential election — featuring a historically unpopular female candidate at a time when political party polarization is historically high — is a prime example of how difficult it is to empirically disentangle sexism from other factors. Consider the fact that, even among people who are excited about the possibility of a woman becoming president, half wish that woman weren’t Hillary Clinton. Is that a sexist position — a way of applying a coat of socially acceptable lipstick to the fact that these people don’t really want to vote for any woman? It’s hard to say. Because the reasons people give for not liking Hillary Clinton are difficult to categorize.

Dan Hopkins, FiveThirtyEight contributor and associate professor of political science at the University of Pennsylvania, is part of a team that has been conducting political surveys using the same respondents for nearly a decade. This year, he’s been asking his subjects open-ended questions about why they don’t like Clinton. Then he categorized the responses in an attempt to quantify the qualitative. From this, we know that explicitly gendered reasoning is relatively rare. In a sample of 1,228 people who disliked Clinton, taken on Oct. 26, only 10 responses were directly tied to gender — “her feminist ways,” for example. Respondents were far more likely to dislike Clinton because of personality traits or lack of trust in her. But some of those responses could also be gender-related. When you dislike “everything” about a female candidate, does that include her sex? When you say “she seems power hungry,” would you say that about a similar man? Science can’t really tell us.

We know at least one similarly qualified man who has generally polled better than Clinton: her husband, Bill. During Bill Clinton’s presidency, Hillary Clinton was typically less popular than he was, which is extremely unusual for a first lady, said Laurel Elder, professor of political science at Hartwick College. And although she was more popular than him from 1998 to 2004 — roughly coinciding with the era of the Monica Lewinsky scandal through her first Senate term — they flipped again after that. As of early August 2016, Gallup had Bill Clinton up 9 percentage points on her. Hillary Clinton’s unpopularity in comparison to Bill’s is interesting, given that they share most of the same policy positions, political scandals and time spent in the public eye.

All of this is to say that we can’t prove it’s sexism that has made people dislike Hillary Clinton, or Michele Bachmann, or Susanna Salter — even when people are making sexist comments about them. Female candidates aren’t being systematically discriminated against at the polls. But, at the same time, those things we can’t measure about sexism and politics are probably having an impact, because they affect how women perceive elections. Remember that one of the biggest goals of political science research in this field is to figure out what’s causing the gender gap in political representation. A major factor in that seems to be that women perceive politics as a hostile environment, choosing not to run because they don’t think they’ll be treated fairly and think their sex will hurt them at the polls.

STATEMENT TRUE FOR PALIN TRUE FOR H. CLINTON Faced gender bias from voters in 2008 49% 84% Too much attention was paid to her appearance 54 67 Experienced sexist media coverage in 2008 campaign 69 65 How potential woman candidates see sexism in past races Source: American University Women and Politics Institute

In 2011, researchers at the American University’s Women and Politics Institute surveyed more than 1,900 men and 1,800 women whose careers and social positions made them well placed to run for public office. The men were 16 percentage points more likely to ever have considered a run, and the women were much more likely to say that elections where they live were highly competitive and that women didn’t do as well. The women were also more likely to judge their own qualifications and set a higher bar to entry than men — 35 percent of men described themselves as “highly qualified” compared to 22 percent of women.

More tellingly, those women based their opinions on what they saw during the 2008 presidential election. Two-thirds of the women surveyed thought Clinton and Palin were at the receiving end of sexist media coverage. More than half thought the public paid too much attention to the women’s appearances. And 84 percent thought Hillary Clinton had faced gender bias from voters — 49 percent thought the same for Sarah Palin.

If Clinton wins this election, it will be interesting to see what impact it has on women’s decisions to run in future down-ticket races. But even then, what potential female candidates would be seeing is a woman who can win an election but who had to deal with being called a “bitch” to get there. It’s possible that just winning isn’t enough to make that trade-off look appealing.