State courts are traditionally recognized as having two sorts of powers: the power to pronounce the law, or jurisdictional powers, derived from the Roman jurisdictio, and the power to command, derived from the Roman imperium. Like State courts, arbitrators have jurisdictional powers, but no powers of commandment. They cannot directly cause the police to intervene to uphold their decisions. An illustration of this fundamental difference between the powers of State courts and those of arbitrators is the exequatur procedure, the purpose of which is to combine the arbitrator's jurisdictional powers with the State court's powers of commandment so as make an arbitral award enforceable.

State courts administer justice in the name of the State from which they derive their powers. Arbitrators, on the other hand, are entrusted with their jurisdictional duties by the parties. This is why they have only the first of the two sorts of powers characteristic of State courts. But this explanation allows the arbitrator's lack of the power of commandment to be relativized, for what is involved here is the power of commandment attached to State prerogatives. In performing their duties, arbitrators have the power to issue instructions to the parties. They thus deliver procedural orders which the parties are obliged to respect. They may summon witnesses and demand that documents be produced. In some legal systems, arbitrators even have the power to impose fines for delay in performance and to take preventive steps. What they lack is the power of coersion.

The difference in the origins of the respective powers of State courts and arbitrators affects not only the scope of such powers but also the way in which State courts and arbitrators perform their duties in international affairs (I), and means that arbitration case law cannot be likened to that of State courts (II).