The “Supreme Tribunal” -- ‘Abdu’l-Baha explains how its members should be universally elected and the impact of its ruling

For example, the question of universal peace, about which Bahá'u'lláh says that the Supreme Tribunal must be established: although the League of Nations has been brought into existence, yet it is incapable of establishing universal peace. But the Supreme Tribunal which Bahá'u'lláh has described will fulfil this sacred task with the utmost might and power. And His plan is this: that the national assemblies of each country and nation -- that is to say parliaments -- should elect two or three persons who are the choicest of that nation, and are well informed concerning international laws and the relations between governments and aware of the essential needs of the world of humanity in this day. The number of these representatives should be in proportion to the number of inhabitants of that country. The election of these souls who are chosen by the national assembly, that is, the parliament, must be confirmed by the upper house, the congress and the cabinet and also by the president or monarch so these persons may be the elected ones of all the nation and the government. The Supreme Tribunal will be composed of these people, and all mankind will thus have a share therein, for every one of these delegates is fully representative of his nation. When the Supreme Tribunal gives a ruling on any international question, either unanimously or by majority rule, there will no longer be any pretext for the plaintiff or ground of objection for the defendant. In case any of the governments or nations, in the execution of the irrefutable decision of the Supreme Tribunal, be negligent or dilatory, the rest of the nations will rise up against it, because all the governments and nations of the world are the supporters of this Supreme Tribunal. Consider what a firm foundation this is! But by a limited and restricted League the purpose will not be realized as it ought and should. This is the truth about the situation, which has been stated.... (‘Abdu’l-Baha, ‘Selections from the Writings of 'Abdu'l-Baha’)