The organization of the Conference was really worked out in the days ahead of Saturday, January 18, the first of the "non-official" meetings coming on January 12. In fact, the leading powers made decisions during the week before the opening which very much influenced the course of the peacemaking. Depending on how you count such entities as French North Africa, and on whether you count India separately from the British Empire (like Australia), you can list between two and three dozen belligerents who actually engaged in the war. Some of these didn't do all that much engaging: Japan, for example, mobilized 800,000 men for the Entente, but only sustained 1,344 casualties.
Several Latin American countries declared war. Some, like Brazil and Cuba, declared their intentions to get troops into combat, but were unable to do more than mobilize some naval units (Brazil) and hospital units (the Cubans sent 100 doctors and nurses to the Western Front). Some, like the Dominican Republic, were essentially protectorates of the United States and were simply forced to declare war. Others declared war for their own purposes. Honduras and Brazil, for instance, followed the example of Australia by interning most of their ethnic German populations (settlers from the nineteenth century) and expropriating their land and wealth. In Brazil, some statesman were extremely pro-war, hoping to cement their power by showing their might. Some governments simply wanted to be represented at the peace conference and therefore declared war at a safe date.
Long and short: dozens of states were represented at the Conference, but only five Great Powers: Britain, France, Italy, the United States, and Japan. The agreements cemented during the week before January 18 simply ignored the smaller powers, as already mentioned. Indeed, the official structure that the committees of the conference would work out technical solutions to each issue, to be approved by the Council of Ten, consisting of the head of government and foreign minister of each of these five Great Powers:
France—Georges Clemenceau/Stephen Pichon
Britain—David Lloyd George/Arthur Balfour
Italy—Vittorio Orlando/Sidney Sonnino
United States—Woodrow Wilson/ Robert Lansing
Japan--Saionji Kinmochi/Makino Nobuaki
This top-down structure, already decided by time the Conference opened, was presented by the president of the Conference, Clemenceau, who pushed it through the January 18 plenary with a kind of one-breath parliamentary ploy: "Are there any objections? No? ... Adopted!"
Many decisions emerged from this Council of Ten (or Supreme Council), but since Japan was purely a Pacific power and had played a much smaller part in the war, the other four heads of government took to meeting together to make decisions not related to Japan , so that participants began to speak of the "Council of Four" as well. Very soon, the meetings of the Four became the arena for some of the most important decision-making. Wilson's statement that the peace should consist of "open covenants openly arrived at" held great sway among the delegates. Yet the limitation of the decision-making to the Four or even the Ten represented quite a restriction of the "open covenant" rule. In fact, news reporters from all countries, but especially the Americans, were stunned that almost all committee meetings were secret. Press secretaries gave very limited general information periodically. Clemenceau ran both the "plenary" sessions and the meetings of the Ten with machine-gun strictness. He often cut off speakers, or simply walked out of the room as he as simply told the assembled gentlemen, "That's all."
This top-down structure is one of the keys to understanding the Paris Peace Conference. Woodrow Wilson was well-known as a "progressive," an American brand of positivist liberal. Having taken much from Comtean and even Saint-Simonian ideas of rule by the scientists or rule by the social engineers, the American positivists very much preferred the mode of rule by experts (see Colonel House's odd book, Philip Dru, Administrator). The French government was likewise influenced by Saint-Simon and by Comtean positivism; indeed, France during wartime was famous for the haughty attitudes of bureaucrats and generals--the top henchmen of the state. And Clemenceau—with roots in the nationalistic liberal Radical Party--cherished his own personal brand of irascible arrogance. Britain's ruling group likewise derived from what one might call top-down liberals. Most of the delegations were indeed quite comfortable with social (and international) engineering. Hence, the top-down structure of the Conference led to decisions being made without true negotiation among all the delegates, and obviously without negotiations with the defeated (and certainly without consulting most of the people concerned). I will come back to this aspect more than once.