It’s not just the clusters of gun-toting protesters at state capitols. In sporadic incidents across the country, disputes over emergency measures have turned into shootings, fistfights and beatings. Stories abound of intimidation over masking. And armed right-wing groups have threatened contact tracers and people who “snitch” on neighbors and businesses violating health orders.

Researchers who study the links between polarization and violence stress that these incidents are still rare and extreme reactions; polls show that the majority of Americans support and are abiding by distancing measures. But there are fears that the pandemic — especially landing in an election year — has the potential to inflame divisions to dangerous levels if left unchecked.

“If we don’t intervene as a nation, as citizens, to begin to correct this identity-based polarization, then the erosion of democratic norms will go even further. And that’s the threat of potential social unrest,” said Tim Phillips, head of the Boston-based nonprofit Beyond Conflict, which tracks polarization and supports peace efforts around the world.