Finally, it would be a masterstroke if those great powers honestly bent on peace would form a League of Peace, not only to keep the peace among themselves, but to prevent, by force if necessary, its being broken by others. The supreme difficulty in connection with developing the peace work of The Hague arises from the lack of any executive power, of any police power to enforce the decrees of the court. In any community of any size the authority of the courts rests upon actual or potential force: on the existence of a police, or on the knowledge that the able-bodied men of the country are both ready and willing to see that the decrees of judicial and legislative bodies are put into effect.

Nobel lecture (1910)