Choosing legislative candidates via primaries: The pivotal role of executive incumbency

How much influence does incumbency have on the way parties nominate candidates? I address this question in the context of Argentina, examining how political parties decide on candidate nomination methods for National Deputies. I argue that holding the governorship creates an imbalanced distribution of resources within a party, leading party factions to lean toward consensus in candidate selection and reducing the likelihood of choosing a primary election. Conversely, when a party lacks the governorship, its provincial party leader may have a weaker influence in deterring primary elections. I also theorize the various situations and resources governors can employ to discourage primary elections, including potential coattail effects, the option of seeking reelection, control over the primaries’ selectorate, and control of the electoral calendar. To test my expectations, I employ a regression discontinuity design, focusing on governors and those who finished as runners-up in lower chamber elections from 1985 to 2023. My findings reveal that governor incumbency decreases the probability of holding a primary election. I conduct further analyses by examining subgroups, considering the governor’s circumstances and the resources I previously theorized as factors influencing primary deterrence. I find that incumbency only deters primaries when the governor and National Deputies elections are concurrent, when the governor is not term-limited, and when they have control over the electorate and the electoral calendar.