Abstract
<p>Allyship—actions by advantaged-group members supporting marginalized groups—is shaped by how groups define “us.” Common-ingroup appeals (e.g., “we are all Americans”) broaden goodwill but often obscure power imbalances, stalling action. Dual-identity appeals (e.g., “Black and American”) can mobilize allies by highlighting injustice. Yet, they risk triggering suspicions of divided loyalty when groups feel threatened. Integrating social, cultural, and evolutionary psychology, we map the catalysts that facilitate and the constraints that inhibit dual-identity allyship. This framework emphasizes reciprocal influences between groups and highlights the importance of marginalized-group receptivity to allyship efforts. We translate these processes into an actionable policy matrix based on perceived injustice and intergroup threat. The matrix specifies when to emphasize dual identities for justice, when to prioritize threat reduction to ensure receptivity, or when to sequence both approaches. Clarifying when a dual identity sustains allyship equips practitioners with tools for lasting intergroup cooperation.</p>