It is now commonplace for scholars to note that the number of international nongovernmental organizations (INGOs) has exploded. But in recent years, the growth rate of INGOs globally and in the United States has stagnated. We argue this stagnation can best be explained by changes in the environment in which INGOs work. Specifically, the now-dense population environment discourages new INGOs from being founded, while also encouraging competition. Analysis of a new, comprehensive dataset on American INGOs between 1992 and 2012 supports the argument, as do case studies of trends within the environmental conservation and democracy assistance sectors. The analysis suggests debates about INGO cooperation and competition overlook a key environmental factor that varies across and within populations of organizations: density. We draw out the implications of this approach for contemporary global governance. ∗Associate Professor (on term), Department of Political Science, Yale University. E-mail: sarah.bush@yale.edu. Website: http://campuspress.yale.edu/sarahbush. †Associate Professor, Department of Government and Politics, University of Maryland. E-mail: jhadden1@umd.edu. Website: http://www.jenniferhadden.com. International non-governmental organizations (INGOs) are central to contemporary global governance, often taking on roles states are unwilling or unable to fill. They monitor elections, provide relief after natural disasters, advocate for human rights, and protect thousands of endangered species. Yet INGOs did not always play substantial roles in world politics. Their number and influence dramatically expanded during the twentieth century (Keck and Sikkink 1998, 11). INGO growth was particularly rapid in the 1980s and 1990s, when shifting geopolitics, technological changes, and new international norms stimulated foundings (Boli and Thomas 1999; Reimann 2006). But the story of INGOs did not end with the close of the 1990s. In fact, our data on global and American INGOs indicate this growth spurt was followed by declining growth rates in the early 2000s, and virtually stagnation by 2010. Meanwhile, critics have increasingly faulted INGOs for inefficiencies, ineffectiveness, and unprincipled behavior (e.g., Cooley and Ron 2002; Bob 2005). Why has the growth rate of INGOs stagnated? More generally, what explains variation in the foundings of INGOs? How do dynamics of INGO populations relate to global governance, which is increasingly “complex” and shaped by the actions of non-state actors (Alter and Meunier, 2009)? Answering those questions is difficult in part because there are few systematic, crosssectoral studies examining when and why INGOs emerge. Moreover, to the extent they have theorized INGO creation, scholars’ explanations do not offer satisfying accounts of decline and stagnation in INGO foundings. The need for INGOs’ services has continued, as INGOs have become central to the implementation of foreign policy (Dietrich 2016) and capture a “large and increasing share” of foreign aid (Büthe, Major and de Mello e Souza 2012, 571). Their role in global policymaking has also become more common, with inter-governmental organizations (IGOs) granting INGOs more access to policymaking (Tallberg et al. 2013). Thus, the decline and stagnation in growth rate is puzzling from the perspective of existing theory, necessitating new thinking.

中文翻译：

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美国国际非政府组织成立的密度与衰落

现在，学者们注意到国际非政府组织（INGOs）的数量激增已司空见惯。但是近年来，全球和美国INGO的增长停滞不前。我们认为，这种停滞可以用国际非政府组织工作环境的变化来最好地解释。特别是，目前人口稠密的环境阻碍了新的国际非政府组织的建立，同时也鼓励了竞争。对1992年至2012年间美国国际非政府组织的一个新的，全面的数据集的分析支持了这一论点，环境保护和民主援助行业内的趋势案例研究也是如此。分析表明，关于国际非政府组织合作与竞争的辩论忽视了在组织内部和组织内部变化的关键环境因素：密度。我们得出了这种方法对当代全球治理的启示。*耶鲁大学政治学系副教授（任期）。电子邮件：sarah.bush@yale.edu。网站：http：//campuspress.yale.edu/sarahbush。†马里兰大学政府与政治系副教授。电子邮件：jhadden1@umd.edu。网站：http：//www.jenniferhadden.com。国际非政府组织（INGO）是当代全球治理的核心，通常扮演国家不愿或无法填补的角色。他们监督选举，在自然灾害后提供救济，倡导人权，并保护数千种濒危物种。然而，国际非政府组织并不总是在世界政治中发挥重要作用。在20世纪，他们的人数和影响力急剧扩大（Keck and Sikkink 1998，11）。INGO的增长在1980年代和1990年代特别迅速，当时地缘政治，技术变革和新的国际规范推动了建国（Boli and Thomas 1999; Reimann 2006）。但是，国际非政府组织的故事并没有在1990年代末期结束。实际上，我们关于全球和美国INGO的数据表明，这种增长突增是在2000年代初期，增长率下降，到2010年实际上停滞不前。和罗恩（2002）；鲍勃（2005）。为什么国际非政府组织的增长停滞不前？更笼统地说，是什么解释了国际非政府组织成立的原因？非政府组织人口动态如何与全球治理联系在一起，全球治理越来越“复杂”，并受到非国家行为者的行动的影响（Alter和Meunier，2009）？回答这些问题很困难，部分原因是很少有系统的，跨部门的研究来研究何时以及为什么出现非政府组织。此外，就他们对INGO创作的理论化程度而言，学者的解释并不能令人满意地说明INGO创立中的衰落与停滞。由于国际非政府组织已成为执行外交政策的中心（Dietrich，2016年）并抓住了“越来越大的份额”的外国援助（Büthe，Major和de Mello e Souza，2012年，第571页），对国际非政府组织的服务的需求仍在继续。它们在全球决策中的作用也变得越来越普遍，政府间组织（IGO）为INGO提供了更多的决策机会（Tallberg et al。2013）。因此，从现有理论的角度来看，增长率的下降和停滞令人迷惑，需要新的思维。