Do nuclear weapons deter low-level military conflict? Although the political effects of nuclear weapons have been debated for more than seventy years, scholarship has yet to produce a clear answer. We design a study that reduces the risk of omitted variable bias relative to prior research. Our analysis compares the rates of conflict among eventual nuclear powers in the periods before and after they obtained an arsenal. We include two-way fixed effects to control for time-invariant state-specific confounders and address common shocks. Our findings indicate that switching from nonnuclear status to a nuclear arsenal decreases the risk of being targeted in militarized interstate disputes (MID) by nonnuclear challengers. However, when it comes to low-level conflict, nuclear powers do not appear to be deterred from instigating disputes with other nuclear-armed states. This result stands in contrast to most prior studies, which conclude that the possession of nuclear weapons increases or does not reliably decrease the risk of being targeted—even for nonnuclear challengers. Although there are clear limits to the deterrence benefits of nuclear weapons at low levels of conflict, states can reduce their vulnerability to some degree by developing a nuclear arsenal.

中文翻译：

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核武器与低级别军事冲突

核武器能阻止低级别的军事冲突吗？尽管核武器的政治影响已争论了 70 多年，学术界仍未得出明确的答案。我们设计了一项研究，以降低相对于先前研究的遗漏变量偏差的风险。我们的分析比较了最终核大国在获得核武库之前和之后的冲突率。我们包括双向固定效应来控制时不变状态特定的混杂因素并解决常见的冲击。我们的研究结果表明，从无核状态转变为核武库可以降低在军事化州际争端 (MID) 中成为无核挑战者目标的风险。但是，当涉及到低级冲突时，核大国似乎并没有被阻止挑起与其他核武器国家的争端。这一结果与大多数先前的研究形成鲜明对比，这些研究得出的结论是，拥有核武器会增加或不会可靠地降低成为目标的风险——即使对于非核挑战者也是如此。尽管在低级别冲突中核武器的威慑作用有明显的局限性，但各国可以通过发展核武库在一定程度上降低其脆弱性。