The features of electoral systems can affect electoral outcomes even for fixed societal preferences. We analyze a quasi-experiment around a staggered change from a paper ballot to an electronic ballot system, which reduces the cost of split-ticket voting. A high cost to split the ticket favors straight-ticket voting, i.e., choosing the same party in all electoral races. If voters care the most about a single-seat race and if they are voting straighttickets, then the single-seat race drives the decision about which party to vote on all races. Therefore, strategic voting considerations on the single-seat race have spillovers to other races, negatively affecting small parties even in races with a proportional representation system. We show how the reduction in the cost to split the ticket increases the number of split-ticket votes and improves the performance of small parties in multiple-seat races. This results in higher political competition.