Political parties learn from foreign incumbents, that is, parties abroad that won office. But does the scope of this cross-national policy diffusion vary with the party family that generates those incumbents? The authors argue that party family conditions transnational policy learning when it makes information on the positions of sister parties more readily available and relevant. Both conditions apply to social democratic parties. Unlike other party families, social democrats have faced major competitive challenges since the 1970s and they exhibit exceptionally strong transnational organizations—factors, the authors contend, that uniquely facilitate cross-national policy learning from successful parties within the family. The authors analyze parties’ policy positions using spatial methods and find that social democratic parties are indeed exceptional because they emulate one another across borders more than do Christian democratic and conservative parties. These findings have important implications for our understanding of political representation and of social democratic parties’ election strategies over the past forty years.

中文翻译：

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社会民主党例外论与跨国政策联系

政党向外国现任者学习，即在国外赢得职位的政党。但是，这种跨国政策传播的范围是否会因产生这些现任者的政党家族而异？作者认为，政党家庭条件跨国政策学习使有关姐妹政党立场的信息更容易获得和相关。这两个条件都适用于社会民主党。与其他政党家族不同，自 1970 年代以来，社会民主党面临着重大的竞争挑战，而且他们表现出异常强大的跨国组织——作者认为，这些因素独特地促进了家族内部成功政党的跨国政策学习。作者使用空间方法分析了政党的政策立场，发现社会民主党确实与众不同，因为它们比基督教民主和保守政党更能跨越国界相互模仿。这些发现对我们理解过去四十年的政治代表性和社会民主党的选举策略具有重要意义。