2. Open diplomacy. The conference was conducted in secret, with only the major powers participating. Small countries and colonies were not allowed to participate in the negotiations.
3. Freedom of trade. The conference imposed tariffs and other trade restrictions that hindered free trade between countries. This violated the principle of the open door policy, which called for equal economic opportunities for all nations.
4. Arms reduction. The conference did not agree to any significant arms reductions. This violated the principle of collective security, which called for the cooperative maintenance of peace through the League of Nations.
5. Fair treatment of Germany. The conference imposed harsh peace terms on Germany, including large reparations payments and the loss of territory. This contributed to the economic and political instability that led to the rise of Nazism in Germany.