This paper studies collective decision-making with interdependent valuations, where, unlike the extant literature, the committee cannot commit to a majority rule, necessitating it to be ex post optimal or “time-consistent”. We find that (1) a majority rule is time-consistent if and only if the expected number of affirmative votes it generates is approximately the rule itself; (2) the preference interdependence exacerbates the commitment problem by creating incentives for strategic (pivotal) voting and in turn expanding the set of time-consistent rules; in particular, any majority rule, including the unanimity, becomes time-consistent under pure common values; and (3) as the committee size grows without bound, the commitment problem disappears owing to the dilution of incentives for strategic voting.