Parties with left-wing positions on economic issues and right-wing (i.e., authoritarian) positions on cultural issues have been historically largely absent from the supply side of the policy space of Western European democracies. Yet, many citizens hold such left-authoritarian issue attitudes. This article addresses the hypotheses that left-authoritarian citizens are less likely to vote, less satisfied with the democratic process and have lower levels of political trust when there is a left-authoritarian supply gap. Using data for 14 Western European countries from the European Social Survey 2008 in the main analysis, it is shown that left-authoritarians are less likely to vote and exhibit lower levels of satisfaction with democracy and political trust. A supplementary analysis of national election studies from Finland before and after the electoral breakthrough of the left-authoritarian True Finns Party in 2011 indicates that whether left-authoritarians participate less and believe less in the efficacy of voting is contingent on the presence of a strong leftauthoritarian party. This study illuminates how constrained party supply in a two-dimensional policy space can affect voter turnout as well as political support, and has broader implications for the potential further rise of left-authoritarian challenger parties.