Why rival powers might cooperate against a shared threat

The space-war analogy produces disagreement over whether an external threat would unite rival human states. One proposed common response rests on self-interest: stronger states would fear that an attacker successful against weaker neighbors would threaten them next. The Boxer Rebellion serves as a historical comparison for a coalition protecting its members' interests. The objection is that an outside power could still buy cooperation with territory or technology, so a shared identity would not guarantee solidarity. The reply accepts that such collaboration could happen initially, but expects it to fail once the collaborators fear that the outside power could turn against them. The scenario remains speculation about future politics, while the historical comparison concerns how rivals can cooperate without resolving their competing interests.