A predictive model of a polarized group, similar to the current U.S. Senate, demonstrates that when an outside threat—like war or a pandemic—fails to unite the group, the divide may be irreversible through democratic means. Published in the Proceedings of the National Academy of Sciences as part of a Dynamics of Political Polarization Special Feature, the model identifies such atypical behavior among the political elite as a powerful symptom of dangerously high levels of polarization.
