 However, the mandate argument faces two major problems. First, even if we assume that such mandates exist, to know whether voting is rational, we would need to know how much the nth voter’s vote increases the marginal effectiveness of her preferred candidate, or reduces the marginal effectiveness of her dispreferred candidate. Suppose voting for the expected winning candidate costs me $15 worth of my time. It would be rational for me to vote only if I believed my individual vote would give the winning candidate at least $15 worth of electoral efficacy (and I care about the increased efficiency as much or more than my opportunity costs). In principle, whether individual votes change the “mandate” this much is something that political scientists could measure, and indeed, they have tried to do so. 