Reconsidering publicness in alliance defence expenditures: NATO expansion and burden sharing

Over the past several decades, NATO allies have debated the relative burdens and benefits of NATO membership. Recently, this concern surfaced as members debated the magnitude and distribution of NATO expansion costs. This paper presents an economic model of defence alliances to identify the benefits and burdens of alliance membership. It suggests that defence expenditures provide public benefits if alliance members share common interests and mutual commitment; defence expenditures provide private benefits if countries lack common interests and mutual commitment. The model's results are used to discuss NATO's evolving roles and missions, NATO expansion and burden sharing across NATO members.