This paper provides an expanded analysis of NATO security burden sharing by including a variety of conglomerate security terms that involve subsets of military expenditure (ME), UN and non-UN peacekeeping contributions, global health spending, UN environmental support, and official development assistance. In so doing, we identify components of security spending that promote or inhibit free riding on allies' security spillovers. Additionally, we examine security burden sharing when the NATO alliance is conceptually augmented to include three key Asia-Pacific allies – Australia, Japan, and the Republic of Korea. The paper's statistical tests for security burden sharing rely on spatial-lag panel models that account for ally connectiveness based on alliance membership, contiguity and US power projection, and allies’ relative locations. Security subsets containing ME display robust free riding or reliance on other allies’ security spillovers, while security subsets not containing ME indicate allies responding positively to security spillovers.
Policy Implications
- During 1991–2021, defense spending free riding continues to characterize NATO. Allies' reliance on the defense spending of other NATO allies holds when these defense spillovers are weighted by membership status, ally contiguity and US power projection, and inverse distance. Most NATO allies must spend more to address defense spending free riding.
- If NATO allies' security spending is broadened to include defense, UN peacekeeping, WHO, UN Environment Programme (UNEP), and foreign assistance spending, security free-riding is attenuated but is still present because defense spending, the driving force for free riding, dwarfs the aggregate of the other security spending measures. Thus, broadening the security measure does not eradicate the need for NATO to stimulate its allies' contributions to their collective security.
- By contrast, security measures, which do not include defense spending, have NATO allies reacting positively to security spillovers of other allies when security includes WHO, UNEP, foreign assistance, and UN and/or non-UN peacekeeping contributions. Thus, NATO's efforts to shore up security spending must focus on the defense spending component.
- As NATO allies allocate more resources to broader security concerns to address the global environment, world poverty, world health concerns, and conflict containment, security free-riding is expected to diminish, thereby diminishing the need for NATO's efforts to increase overall security spending.
- Security free-riding is still an issue when defense spending is part of the security measure for NATO and its three Asia-Pacific partners (Australia, Japan, and the Republic of Korea). Current NATO efforts to tighten that partnership in confronting Asian threats will not end defense free-riding concern, therefore requiring these allies' efforts to stimulate security spending.
Photo by George Becker