Individuals use facial width-to-height ratio (fWHR) to infer formidability in men. We hypothesized such broad assessments of target formidability from fWHR would form a basis for determining men’s coalitional value, with high-fWHR men being especially valuable in roles requiring physical strength. Across five studies (N=1,315), we assessed how affordance judgments of formidability influence coalitional decisions. In addition to replicating previous findings indicating high-fWHR men are more desirable for tasks requiring physical strength (Study 1), we found a perceptual basis for these decisions (Studies 2a and 2b). In two pre-registered studies, we found that activation of competitive motivations heightens individuals’ interest in formidable allies during intergroup interactions (Study 3), but not interest in approaching them (Study 4). We interpret findings using evolutionary and social affordance theories and discuss hypothesized ancestral origins of selecting formidable allies.