How do electoral rules affect the poor? When do parties have an incentive to stand as the party of low-income citizens? When will parties mobilize the electoral support of low-income voters? This discussion presents evidence that rates of turnout among,low-income citizens reflect legislators’ and parties’ electoral incentives to be responsive to the poor, and that these electoral incentives are determined by electoral geography – the joint geographic distribution of legislative seats and low-income voters across electoral districts. Further, this discussion demonstrates that under SMD electoral rules, low-income voters are more likely to vote in those electoral districts in which they are likely to be pivotal. By presenting a strategic mobilization account of voter turnout, this discussion breaks with current accounts of voter turnout that emphasize facilitative and motivational individual and system-level factors. Instead, this discussion argues that low-income voters’ turnout decisions, in fact, reflect parties’ electoral incentives to cultivate and mobilize a low-income constituency.