This article investigates why, in two different political and institutional contexts, leftist governing parties became agents of empowered inclusion, boosting the capacity of subordinate social actors to shape the agenda of politics and allowing them to push social policy in an inclusionary direction. To explain how and why this happened, it highlights the ambiguous nature of party-society linkages. While societal ties are necessary for sustained significant progress in social and political inclusion, they can also block the later consolidation of achievements. This happens as some groups, once included, block further inclusion. We build our theoretical argument about the two-sided nature of party-society linkages using comparative evidence from Bolivia and Uruguay—two countries where progress toward empowered inclusion has been especially notable in the past two decades. The article contributes to existing scholarship on social and political inclusion by calling for greater attention to the critical but, at times, ambiguous role that the social bases of parties play.

本文探讨了为什么在两种不同的政治和制度背景下，左翼执政党成为赋权包容的代理人，提高了从属社会行为者塑造政治议程的能力，并允许他们将社会政策推向包容性方向。为了解释这是如何发生的以及为什么会发生，它强调了党与社会联系的模棱两可的性质。虽然社会联系对于社会和政治包容的持续重大进展是必要的，但它们也可能阻碍后来的成就巩固。发生这种情况是因为某些团体一旦被纳入，就会阻止进一步纳入。我们使用来自玻利维亚和乌拉圭的比较证据来构建我们关于政党与社会联系的双边性质的理论论证——这两个国家在过去二十年中在赋权包容方面取得了特别显着的进展。这篇文章呼吁更多地关注政党的社会基础所扮演的关键但有时模棱两可的角色，从而为现有的社会和政治包容性学术研究做出了贡献。