during world war i kessler and karl gustav vollmoeller worked together at the german embassy in bern for the cultural department of the foreign office. they developed activities aimed at peace plans with france and england. in november 1918, kessler was german ambassador to warsaw in the newly independent poland (second polish republic). in 1919 he wrote a "plan for a league of nations on the basis of an organization of organizations (world organisation)", which contains the constitution of such an international confederation of states. the purpose of this covenant was above all to prevent new wars, securing human rights and the regulation of world trade. main body of this covenant would be the "world council", which also elected an executive committee. under his plan a "weltjustizhof", a world court of arbitration and administrative authorities would be built. this ordered by paragraphs plan had the form of a state constitution. another plan for a supranational organization he developed in 1920 as "guidelines for a true league of nations" in the form of a resolution. in 1922 he served for a short time as the president of the german peace society, of which he was a member from 1919 to 1929.