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What The Yankees-Red Sox Rivalry Can Teach Us About Political Polarization

A few weeks ago, FiveThirtyEight fielded a SurveyMonkey poll to baseball fans in the Northeast. In the survey,1 I asked 1,071 people which baseball team they supported (if any), how strongly they supported the team, and then I asked them this:

How upset would you feel if you had a son or daughter who married a Boston Red Sox/New York Yankees/New York Mets/Philadelphia Phillies fan?

Red Sox fans were asked about marriages to Yankees fans and vice versa. Mets and Phillies fans were asked about each other.2

I asked this question about baseball because I think it can help us understand something important about politics.

Since 1960, survey researchers have asked Americans if they would be upset if they had a son or daughter marry someone of the other political party. Researchers have asked this question to gauge the extent that politics affects personal relationships and nonpolitical aspects of our lives. In 1960, about 5 percent of Democrats and Republicans said they would be upset. In 2008, when political scientists Shanto Iyengar, Gaurav Sood and Yphtach Lelkes revived the question, 27 percent of Republicans and 20 percent of Democrats said they would be somewhat or very upset about a child marrying someone of the other party. These authors, as well as researchers at Pew Research Center, have asked the question several times since 2008, with similar results.

What do we make of so many Democrats and Republicans now saying they would be upset about their kids marrying outside their party? After all, plenty of Democrats marry Republicans. Do a quarter of partisans genuinely feel so strongly? You might get that impression from public opinion surveys in which respondents report that they don’t like people in the other party, that they would only want to live in neighborhoods where people share their political views, and that they believe the other party is a threat to the nation.

When survey respondents are asked questions about politics, however, they are primed to think in partisan terms. They start playing the role of a partisan. And they start saying things they probably don’t believe. Talk is cheap.

That’s why I wanted to ask this question about baseball. The baseball version of the question operates like a placebo. Baseball allegiances are strong and enduring, but they obviously do not convey important moral values or issues in the way that party affiliations convey. Whether your team wins the World Series does not affect the long-term well-being of a country. But if you remind people of an allegiance they hold, even a superficial one, maybe they will claim the allegiance would affect their personal relationships.

The results for baseball fans were surprisingly consistent across teams. For each team, 17 to 20 percent of fans said they would be upset if they had a son or daughter marry a fan of the rival team. Overall, 18 percent of fans said they would be upset.

Yankees fans 236 Red Sox fans 17.4%
Red Sox fans 181 Yankees fans 18.2
Mets fans 92 Phillies fans 19.6
Phillies fans 101 Mets fans 19.8
Republicans 320 Democrats 18.8
Democrats 503 Republicans 32.2
There’s just as much polarization in baseball as in politics

Poll conducted July 11-17 among Northeasterners.


For the sake of comparison, I also asked these survey respondents the political version of the question, first asking them about their party and then asking if they’d be upset if their child married someone from the other party. (I randomized whether respondents saw the politics questions first or the sports questions first.)3

When Republicans were asked about their son or daughter marrying a Democrat, 19 percent said they would be somewhat or very upset; that’s the same percent as with baseball fans. Democrats were more likely to say they’d be upset about a Republican marriage, with 32 percent saying so. (In national surveys, Republicans tend to be more upset about this than Democrats, but not in this sample restricted to Northeasterners.) Because Democrats outnumber Republicans in the Northeast, overall 27 percent of partisans in the sample report being upset.4

While more political partisans claim they would be upset than baseball partisans, the difference is not very big, considering the difference in meaning between these two kinds of allegiances. What’s more, this survey was fielded at an intense moment in politics but not in baseball. We are in the sleepy middle of baseball season and these four teams have much bigger problems in their divisions than their classic rivals. But even at this particular moment in time, almost as many baseball fans report being upset as Democrats and Republicans about intermarriage across their respective sides. To put it another way, baseball fans in 2016 are four times more likely to be upset about fan intermarriage as Democrats and Republicans were upset about partisan intermarriage circa 1960.

Probably the wrong interpretation of this result is: “Wow, people in the Northeast really take their baseball seriously!” The more plausible interpretation is that these survey respondents are not conveying their true beliefs, neither about baseball nor about politics. It is probably not the case that 1 in 5 baseball fans would truly be upset if their kid married a fan of the other team. And the same is likely true for 1 in 4 partisans. When surveys prime people to think of themselves as fans of a sports team or as partisans of a political party, they play a role.

Partisan polarization is often not about issues or ideology, but about social identity, teamsmanship and feelings of who is the in-group and who is the out-group (e.g., here and here). When a survey researcher, a political campaign, or a sportscaster encourages people to think and feel like a partisan, people will do so. That’s true if the team is trying to win a World Series or run a country. Democrats and Republicans will cheer, boo, emote and say outlandish things because it is easier and more fun to think about politics in terms of us-vs.-them competition, just like with sports.

As I have argued elsewhere, we should be concerned about politics being treated this way. I can hate the Yankees, feel wronged that Tom Brady is benched for a few games, and make the absurd claim that I would be very upset if my sons married Yankees fans. In sports, irrational partisan feelings are permissible because the stakes are so low. Irrational partisan emotions clearly exist in politics, too, but in politics we should be ashamed of them.


  1. The survey was fielded July 11-17 among people Maine, Massachusetts, New Hampshire, Vermont, Rhode Island, Connecticut, New York, New Jersey and Pennsylvania.

  2. Among respondents, 57 percent said they were fans of the Red Sox, Yankees, Mets or Phillies. Another 11 percent said they were fans of another team (mainly the Pittsburgh Pirates), and 32 percent said they were not baseball fans.

  3. Partisans here include “leaners” who first identify in a survey as independent but then say they lean toward one party or another. As John Sides has discussed, independent leaners behave a lot like partisans.

  4. If I restrict the sample just to people who claim they are strong sports fans and strong partisans, I find that that 27 percent of sports fans say they would be upset, compared with 35 percent of strong Republicans and 55 percent of strong Democrats.

Eitan Hersh is an assistant professor of political science at Yale University.