Threat of a common enemy may no longer unite polarized Americans, study finds

During World War II, Americans united. They ate less meat and planted victory gardens. They lowered the thermostats and rationed their gasoline. Republican, Democrat, it didn’t matter: against a common enemy, American civilians were ready to sacrifice themselves in the name of American interests.

That was 80 years ago, when the political climate was less marked by partisan animosity. In 1960, 10% of parents said they would be uncomfortable if their child married someone from the opposing political party. In 2010, this figure was 33%.

“Intuitively, it makes sense for common enemies to unite people. It’s a popular theory that dates back to ancient Sanskrit writings,” said Douglas Guilbeault, assistant professor at Berkeley Haas. “Given the current state of polarization, the question is whether we can get Republicans and Democrats to work together in the face of a common threat.”

In new research published in the journal Nature Science Reports, Guilbeault and six co-authors found the opposite. The series of experiments found that exposing supporters to information about a common enemy instilled in Republicans a deeper distrust of Democrats than they did when they started. This was not the case for the Democrats in the study.

Experiences

The researchers recruited approximately 1,700 Republicans and Democrats between October 2019 and January 2020 to participate in a survey. Participants were divided into three groups and each read a different Reuters article: one with a patriotic slant on July 4 celebrations in the United States; another – chosen to evoke a “common enemy” – on how Russia, Iran and China were conspiring against the United States; and the third a neutral article on the first human drawings discovered in South Africa.

In the second stage of the experiment, participants were told that they could earn additional money based on the accuracy of their answer to the question: “What percentage of immigrants between 2011 and 2015 had made college studies? After giving their answers, participants received a response supposedly generated by a member of the opposing political party. (In fact, it was generated by a bot programmed to give a “hypothesis” that differed from the participant’s by about 50 percentage points.) Participants were then given the opportunity to revise their hypotheses.

“The extent to which someone used information from the other party to update their estimate gave us some insight into the cooperation between the parties,” Guilbeault said.

What they found was that only reading the “common enemy” article about Russia, Iran and China moved people’s assumptions, and that seemed to increase the animosity rather than bringing people together. Specifically, Republicans who had read the article were less willing to use information provided by Democrats. The effect was stronger among those who described themselves as more conservative.

Real-world threats increase partisanship

The research project took an interesting turn when, on January 3, 2020, US special forces in Iraq assassinated influential Iranian general Qassim Suleimani. News was saturated with the event and fear of war grew at home and abroad. This was halfway through the researchers’ study, and the events provided a natural experience alongside the investigative experience – a real-time American threat alongside the more abstract threat of a news story.

Researchers found that after Suleimani’s assassination, Republican participants identified much more strongly as Americans and were much less likely to cooperate with Democrats.

Asymmetric polarization

The finding that Republicans reacted differently from Democrats may be explained by “asymmetrical polarization,” Guilbeault said. A recent Pew Research Center survey found that Republicans were significantly more likely than Democrats to view the other party as un-American and a threat to the nation’s well-being (36% of Republicans vs. 27% of Democrats ).

Different parties’ views on what it means to be “American” could be behind the different reactions, the researchers theorize. While a “common enemy” prompt might have caused people to see themselves as more “American” and brought them closer together, the presentation of an outside threat may instead have further inflamed divisions.

“Because Democrats and Republicans seem to have very different definitions of what it means to be an American, you can actually create more conflict by having them identify themselves that way,” Guibeault said. “We find evidence consistent with this backfire effect here.”

(He acknowledged that it’s also possible that this particular threat resonates more with Republicans than Democrats, and the results could vary with a different threat.)

Consequences

The fact of contemporary polarization has been well documented in academia and the popular press. But what this polarization means for the country’s health remains unclear. As Guilbeault and his colleagues have demonstrated, a key implication is that partisan tensions, when high enough, can cause political rivals to see each other more as an external enemy than a source of mutual strength.

This idea should put us on alert ahead of the next election, which is expected to be one of the most polarizing yet, Guilbeault said.

“We saw it with COVID, where there was a common enemy and each side was just pointing fingers at the other,” he said. “Intensely polarized societies seem to create this backfire effect where, rather than bringing groups together, exposure to a common enemy makes them more likely to accuse each other of being on the enemy’s side.”