NATO’s 2023 summit in Vilnius was dominated by Russia’s war against Ukraine. The summit in Washington, D.C., in July 2024 will be influenced by an additional major conflict in NATO’s neighbourhood: the war in Gaza and the related heightened tensions in the Middle East. These have also...

We investigate the role of networks of military alliances in preventing or encouraging wars between groups of countries. A country is vulnerable to attack if there is some fully-allied group of countries that can defeat that country and its (remaining) allies based on a function of their...