How strategic are party members when voting for party leaders? Evidence from a conjoint experiment

Despite widespread trends toward decentralizing leadership selection, party members still hold a monopoly over leader selection in most democracies. Yet, the factors shaping their voting behavior in leadership contests remain underexplored, and the absence of experimental evidence limits causal claims. Party members are often considered more ideologically extreme than party leaders, and youth wing members even more so. Moreover, while policy, office, and votes are key party goals, their relative importance remains uncertain. This raises a critical question: To what extent are party members willing to trade off policy agreement for electoral gains in leadership contests? I conduct a conjoint survey experiment with over 5,000 Portuguese party members to test pre-registered literature-driven hypotheses about whether they prioritize policy agreement over electoral appeal in leadership elections and whether youth wing members are even more likely to do so. The findings have large implications for the literature on leadership and candidate selection, the personalization of politics, intra-party democracy, and the growing study of party youth wings.