On 4 June 1943, a military coup crushed Argentina's democracy, marking the end of the oligarchic era and ‘planting the seeds’ of Peronism. This case sheds light on how rulers’ mistakes can operate as a key independent variable in producing regime changes. We argue that the former conservative president, Ramón S. Castillo, provoked an otherwise avoidable democratic breakdown. Specifically, Castillo's misguided relationships with regime insiders and outsiders unintentionally eroded political stability and triggered the fall of democracy. Until now, agent-based scholarship has fallen short in tracing incumbents’ mistakes and linking them to regime-change processes. We test the argument by conducting a within-case analysis of Argentina's democratic fall in the early 1940s, scrutinising the president's errors at five critical events. We conclude that critical-event analysis can help disentangle the role of leaders’ mistakes in other episodes of regime change.

1943 年 6 月 4 日，一场军事政变摧毁了阿根廷的民主，标志着寡头时代的结束，并“播下了庇隆主义的种子”。这个案例揭示了统治者的错误如何作为导致政权更迭的关键自变量。我们认为，前保守派总统拉蒙·S·卡斯蒂略引发了本来可以避免的民主崩溃。具体来说，卡斯蒂略与政权内部和外部人士的错误关系无意中侵蚀了政治稳定并引发了民主的垮台。到目前为止，基于代理人的学术在追踪现任者的错误并将其与政权更迭过程联系起来方面还不够。我们通过对 1940 年代初阿根廷民主衰落进行案例内分析来检验这一论点，仔细审查总统在五个关键事件上的错误。我们的结论是，关键事件分析可以帮助理清领导人的错误在其他政权更迭事件中所扮演的角色。