When Elbridge Gerry proposed in the [Constitutional] Convention that no standing army exceed three thousand men, Washington is supposed to have made a countermotion that "no foreign enemy should invade the United States at any time, with more than three thousand troops."
That is from Gordon Wood, Empire of Liberty
It seems Gerry would have agreed with Bryan's proof that national defense is not a public good, but Washington begged to differ.
My view is that people tend to view the competition for status partly in group terms. In the Cowen-Hanson view, that competition for group status is what gives rise to political loyalty. Remember, politics is not about policy. It is about group status.
Group status competition also means that there is a strong propensity for group violence. The goal of a military hegemon is to restrain this group violence. It helps for the hegemon to have goodies to hand out to pacify some groups and to have overwhelming military prowess with which to intimidate others.
I'll believe that we can live without hegemony when I see signs that group status competition and group loyalty have disappeared from human nature.