We investigate the effects of voting power in a committee in which one member (the chair) holds, on top of a regular vote, also the power to break ties. The committee captures a situation of conflict between members in which tie-breaking power confers no real power under fully rational strategic voting. Behavior in two independent experiments, however, reveals that tie-breaking power is large and real. Importantly, the chair’s advantage is only partially due to exercising tie-breaking power. Its main source are outcome-space distortions, induced by the asymmetric tie-breaking rule, which become relevant as soon as voting deviates slightly from fully rational strategic voting. Our findings are informative about the effects of power asymmetries in voting bodies in general and for designing institutions robust to boundedly-rational voting behavior.