Studies on party system collapse or individual-party breakdowns view programmatic inconsistency or convergence as necessary for abrupt party system change. In theory, a new or fringe contender can suddenly emerge and disrupt the party system under such circumstances. We test that claim by examining Nayib Bukele’s 2019 presidential election victory in El Salvador. With data from the AmericasBarometer, we estimate probit models and predictive margins to examine the individual-level determinants of disruption in an institutionalised and ideologically polarised party system. The empirical results reveal that Bukele won amid salient ideological differences between traditional parties and that critical views towards democracy fueled his core support. Therefore, we conclude that a significant disruption in an institutionalised party system can occur notwithstanding robust ideological differences between leading contenders. Critical attitudes towards democracy can represent a driving force behind a party system’s disruption.

关于政党制度崩溃或个别政党崩溃的研究认为，程序的不一致或趋同是政党制度突然变化所必需的。理论上，在这种情况下，一个新的或边缘的竞争者可能会突然出现并扰乱党的制度。我们通过研究 Nayib Bukele 在萨尔瓦多的 2019 年总统选举胜利来检验这一说法。利用 AmericasBarometer 的数据，我们估计概率模型和预测边际，以检查在制度化和意识形态两极分化的政党体系中破坏的个人层面决定因素。实证结果表明，布克勒在传统政党之间存在显着的意识形态差异的情况下获胜，而对民主的批判性观点为其核心支持提供了动力。所以，我们的结论是，尽管主要竞争者之间存在强烈的意识形态差异，但制度化的政党体系仍可能发生重大破坏。对民主的批判态度可以代表政党制度瓦解的驱动力。