Abandonment fear is one half of the "alliance security dilemma" articulated by Glenn H. Snyder in his 1984 World Politics article "The Security Dilemma in Alliance Politics" and elaborated in his 1997 book Alliance Politics. Snyder argued that allied states constantly trade off two risks: being abandoned (the partner defects, de-aligns, or fails to fight when needed) and being entrapped (dragged into a conflict that serves the partner's interests but not one's own). Reducing one risk typically increases the other.
Abandonment can take several forms: outright realignment with the adversary, formal renunciation of the alliance treaty, failure to provide promised military or economic support during a crisis, or a more diffuse weakening of commitment signals. Because alliance treaties are rarely self-enforcing, states watch closely for indicators of resolve — defense spending, force posture, leadership statements, and behavior in prior crises.
The concept is central to debates over extended deterrence and the credibility of security guarantees. NATO members, for example, have periodically expressed abandonment concerns about U.S. commitments under Article 5, particularly when Washington signals retrenchment or burden-shifting. Similar anxieties shape Japanese and South Korean debates about the U.S. nuclear umbrella, and Taiwanese assessments of American "strategic ambiguity."
Abandonment fear helps explain several recurring behaviors:
- Hedging — diversifying security partners or building independent capabilities (e.g., French nuclear force de frappe).
- Loyalty signaling — costly contributions to allied operations to lock in reciprocal commitment.
- Tight alliance management — frequent consultations, joint exercises, and forward-deployed forces.
The concept draws on realist assumptions about anarchy and self-help but is also used by neoliberal and constructivist scholars examining how institutions, reputation, and shared identity can mitigate — though rarely eliminate — the underlying uncertainty about an ally's future choices.
Example
In 2017, several European leaders publicly voiced abandonment fears after U.S. President Donald Trump initially declined to explicitly endorse NATO's Article 5 mutual-defense clause during a summit in Brussels.
Frequently asked questions
Political scientist Glenn H. Snyder developed it as part of the alliance security dilemma in his 1984 World Politics article and his 1997 book Alliance Politics.
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