<p>Why do ethnic markers consistently outperform economic position as bases for political coalition, even when material interests would favor cross-ethnic alliance? This article advances a theoretical framework centered on the activation problem. Drawing on the alliance detection system identified in evolutionary psychology and building upon the ecological availability framework from prior research, the current analysis argues that ethnic markers enjoy advantages in political mobilization because ethnic cues possess greater ecological availability, denser institutional infrastructure, and lower coordination costs relative to economic position. This differential cue ecology reconciles two apparently contradictory findings. Laboratory research demonstrates that racial categorization is a reversible byproduct of coalitional cognition, yet field evidence shows ethnic mobilization consistently proves easier than class mobilization. The resolution lies in recognizing that reversibility requires deliberate restructuring of the cue environment—a restructuring that modern institutional arrangements systematically favor for ethnic identities. The framework also extends beyond ethnicity to analyze how nations, religions, and other imagined communities function as activation technologies with varying cue ecologies and inherent fragmentation tendencies. Historical cases from the collapse of the Second International to the Battle of Blair Mountain illustrate the framework’s explanatory power. The analysis generates testable predictions about conditions under which economic position might overcome its activation disadvantages and addresses the deeper question of whether large-scale human solidarity can transcend the tribalistic defaults of coalitional cognition.</p>