Successful federations have "enforceable executive authority" (p. 177)

1. federal must be slightly stronger than its strongest member
2. members relatively homogeneous in size
   • else the strongest members will refuse to contribute to federal organ that can overshadow themselves
   • smaller member states must be able to stand together against the bigger

And the small member states could not conceivably make up for the deficiency of the big. Hence the pathetic emphasis of large-power unions such as the United Nations or the European Council on good will. But good will has no executive authority, and without executive authority no political organism can exist. As a result, large-power unions are able to live only by the grace of their large members who can, and do, veto them out of existence at will.

[...]

As a result, if we are interested in creating international unions not only effectively but also economically, peacefully, and democratically, we must fall back on the organizational principle which alone contains the secret of success, the small-cell principle, and apply the curative principle of division to every federal structure containing big powers.

— breakdown-of-nationsp. 177

"Gini coefficient" for states in federations