Nonproliferation of Nuclear Weapons

Nuclear Reversal of U.S. Allies

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According to a widely-shared assumption among both policy makers and IR scholars, the protection provided by an alliance relationship with the United States constitutes an effective instrument to make allies abandon their existing nuclear weapons activities – a phenomenon that the literature calls “nuclear reversal.” However, this causal explanation is not supported by the data unearthed in this research project.

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Put precisely, the original explanation fails to account for the following two patterns: First, some states have continued their nuclear weapons activities and have become full-fledged nuclear weapons states in spite of their alliance with the United States. And second, even in those U.S.- allied nations where the government decided to give up all nuclear weapons activities, typically some political leaders of the same nation steadfastly refused to support this course of action. The research project set out to explore this puzzle, examining why some political leaders of U.S. allies consent to their nation’s nuclear reversal while others consistently reject this course reversal.

To explain the different propensities of U.S.- allied leaders to agree to a nuclear reversal, the research project tested a diverse set of hypotheses derived from IR theory and social psychology. Methodologically, the project conducted in-depth case studies of South Korea, West Germany, Pakistan, and Great Britain, employing detailed historical process-tracing based on published primary sources and extensive archival research in three countries.

Revealing new and unexpected data, the four case studies have contributed significantly to our understanding of the drivers of nuclear reversals of U.S. allies. 

Key findings are:

  • First, the widely-held assumption that satisfying an ally’s security needs is the key mechanism for making allied decision-makers agree to their nation’s nuclear reversal is not empirically valid. Our results demonstrate that the most relevant mechanism for allied nuclear reversal is the political dynamic that is initiated by the U.S. outright demanding and pushing for a nuclear reversal even vis-à-vis its closest allies. 
  • Second, to the extent that these U.S. demands that its allies agree to a nuclear reversal were successful, this outcome was not driven by accompanying threats of U.S. sanctions, as more recent research has claimed. Rather, archival research has revealed that social pressure was far more effective when inducing U.S. allies to give up their nuclear weapons activities. The success of this strategy of social pressure was not intimately tied to any material U.S. sanctions (i.e. threats of abandonment or economic sanctions) – more important was the concern of allied leaders for being on the same page with the United States as their major ally and international partner.
  • Third – and this represents the core finding of this project –, only some political leaders of U.S. allies reacted to social pressure as described above. The key factor influencing whether a political leader gives in to U.S. social pressure to undertake a nuclear reversal is his (or her) intuitive belief of how high his (or her) nation ranks vis-à-vis its U.S. ally. Leaders who rank their nation clearly below the United States on the international pecking order do not dare to reject the explicit demands of their American protector and therefore consent to their nation’s nuclear reversal. In contrast, those allied political leaders who conceive of their nation as an important power enjoying a status on par with the United States, do not bend to U.S. social pressure and typically reject a nuclear reversal. The key variable influencing the choice over a nuclear reversal of U.S. allies is hence not the international environment; rather, what is crucial is which political leaders hold the key offices at a particular point in time.
  • Finally, this finding allows for a positive outlook for international nonproliferation efforts. For most of those U.S. allies which might be tempted to “go nuclear “ in the future (namely Saudi Arabia, Egypt, the United Arab Emirates, South Kora, Japan, and Taiwan) are led by leaders who seem to rank their nation clearly below the United States and should thus be highly susceptible to U.S.-led social pressure.

Key publications from this project:  

Schneider, J. (2015). "Bringing the First Image of Nuclear Politics Back In. Plädoyer für eine verstärkte Einbeziehung des Individuums in die theoretische Analyse der Proliferation von Kernwaffen." Zeitschrift für Außen- und Sicherheitspolitik, 8 (1). 
Schneider, J. (i.V.). "Amerikanische Allianzen und Nuclear Reversal" (book-length thesis: work in progress).
Schneider, J./Thränert, O. (2014). "Dual Use. Dealing with Uranium Enrichment" 
(= CSS Analyses in Security Studies, No. 151). Zurich: Center for Security Studies. 
Schneider, J. (2014a). "Nuclear Nonproliferation in the Context of U.S. Alliances. Protection, Status, and the Psychology of West Germany’s Nuclear Reversal" (Paper prepared for the International Studies Association Annual Convention in Toronto, March 26-29, 2014). 
Schneider, J. (2014b). "Statusvorstellungen, Gehorsamsbereitschaft und die Einstellung von Kernwaffenaktivitäten bei Allianzpartnern der USA" (Papier für die Vierte Offene Sektionstagung der Sektion Internationale Politik der Deutschen Vereinigung für Politische Wissenschaft in Magdeburg, 25.-27. September 2014).
Schneider, J./Gerzhoy, G. (i.V.). "Farewell to the Nuclear Free-Riding Logic. Why Trust in U.S. Protection Is Not a Prerequisite for Nuclear Reversals of U.S. Allies" ( work in progress).


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