NATO military capabilities and the Russian threat: A difference-in-differences analysis of the 2014 Russian invasion

Abstract

Following the 2014 Russian invasion of Ukraine and annexation of Crimea, most research examining NATO’s response has focused on defence spending. Far less attention has been paid to whether and how NATO members’ military capabilities  – the outputs of defence investment – changed in response to the Russian threat. We examine this case to understand how external security threats shape state military capabilities. Using a difference-in-differences research design and leveraging data on NATO military capabilities from 2008 to 2022, we evaluate how proximity to Russia influenced post-2014 capability adjustments among twenty-nine European NATO allies. We find that NATO allies bordering Russia significantly increased military personnel relative to more distant allies, with a similar but less robust pattern for armoured vehicles. While existing research shows that overall NATO defence spending increased after 2014, we show that this did not uniformly translate into more military equipment and personnel across the alliance. These findings reflect enduring challenges with burden-sharing and the influence of domestic political economies over defence matters. While we find no evidence that the capability increases among frontline NATO allies are fully accounted for by higher defence expenditures, these findings suggest that geographic threat exposure independently shapes states’ capability adjustments beyond what spending levels alone predict.