We define and study social constraints for rational agents. Our work is com
plementary to work on mechanism design in economics and Distributed Artific
ial Intelligence, as well as to work on artificial social systems. In our s
etting agents are rational but obey social laws that are imposed by the sys
tem's designer. Agents can be obliged to obey some social constraints, but
not any constraint can serve as part of the social law. The main theme of o
ur work is the study of settings where there are restrictions on the constr
aints that can serve as social laws. In such settings the designer should f
ind social laws that can be imposed on the agents, and that will lead ratio
nal agents to satisfactory behavior. Our study is carried out in the contex
t of zero-sum and general-sum games (with complete and with incomplete info
rmation) in extensive form.