Alliances and strategic advantage in sequential-move contests: Implications for offensive vs. defensive strategies

This paper examines the impact of alliances and moving order on strategic advantage, conflict intensity, and expected payoffs in three-player sequential-move contests. The study shows that in a scenario where multiple players act as defenders while facing aggression from a lone player that moves first as an attacker, they must make their arming decisions jointly to gain a strategic advantage. Conversely, when attacking a lone player that moves second as a defender, multiple players acting as first movers must make their arming decisions autonomously. Compared to the benchmark equilibrium in a simultaneous-move game, the overall conflict intensity is higher if multiple players arm independently and lower if they arm cooperatively as an alliance. The expected payoffs of all players are the highest in a sequential-move game when two players ally, regardless of their moving order. Based on the analysis, we find that it is effective to launch an offensive strategy when allied players make arming decisions autonomously and strike first as attackers. On the other hand, a defensive strategy is effective when allied players make arming decisions collectively and move second as defenders.