Costs associated with voting affect an individual's willingness to turn out for an election as well as aggregate rates of voting across political jurisdictions. Barriers to participation also skew the social and economic composition of electorates. In this Research Note, we suggest that the costs of participation affect candidate behaviour as well – the strategic purposes of their appeals to voters and the media they choose to deliver messages. Why? By making the trip to the ballot box more or less difficult, electoral laws select voters with respectively less or more interest in and thus knowledge of politics. Given the systematic variations in how people with different levels of political knowledge learn during a campaign, we anticipate that election laws ultimately influence the communication tools that candidates use.

We propose that the costs of voting have a compositional effect on electorates: as voting becomes increasingly difficult, the average level of political knowledge and interest among voters should decrease. This is not due to a micro-level effect in which registration laws somehow make individual voters smarter or better informed. Institutionally imposed costs simply affect who can and will vote. For a brief example, if one state charged its citizens £50 to vote while another paid its citizens £50 at their polling site, we would expect quite sizeable differences in turnout and composition of the electorate across the two states. The main contribution of this note, however, is our recognition that campaigns adapt to these differences in systematic ways. Real world differences in the cost of voting are not as great as these financial disparities, but the idea is the same: costs borne by individuals will have selection effects that produce different types of electorates and prompt different campaign styles by candidates.