International threats unify a nation while internal instability divides it

Evidence

For example, following Allport, we anticipate that whereas internal instability is likely to generate antagonism between groups within a nation, international instability may foster recategorization at the national level that leads to more inclusive ingroup representations (Gaertner & Dovidio, 2000) and to more harmonious internal relations. — John F. Dovidio, Peter Glick, Laurie A. Rudman, On the Nature of Prejudice, 1517

Categorization

• XREF: The rally-around-the-flag effect, familiar from political science work on foreign policy crises; also echoes Simmel’s thesis on external conflict increasing internal cohesion. — connects to: Removing a named external threat intensifies rather than softens dominant-group nationalism. — Nadim N. Rouhana and Nadera Shalhoub-Kevorkian, When Politics Are Sacralized:…, 1391