International social democracy fell apart when the World War began in 1914. In all countries, whether or not they were among the belligerents, three currents may be discerned. On the right side, were the majority socialists, who, depending on their nationality, were for or against a separate peace with Russia. On the left side, were the internationalists, revolutionaries, and pacifists, united in the International Socialist Committee (ISC). This group is usually called the Zimmerwaldians, for their constitutive meeting in Zimmerwald, Switzerland 1915. In the middle was the Bureau of the Socialist International (BSI) led by the Belgian Camille Huysmans, who prudently tried to mediate between socialists from belligerent countries.
The BSI decided to locate in neutral Stockholm on 15 April 1917. The Zimmerwaldians did the same. A "Dutch-Scandinavian Committee" began to advocate for a peace conference. The Petrograd Soviet formed a third party, with Bolsheviks, Mensheviks, and Socialist-Revolutionaries still united briefly after the 1917 February Revolution.
In May it had become clear that the British, French, Belgians, and Russians would oppose a conference. A seemingly endless series of bilateral negotiations, preliminary meetings, tripartite discussions, and cross-initiatives then took off. The Zimmerwaldians had a conference in Stockholm to decide whether they would join the Stockholm conference, and the Russians presented their own peace initiative. Eventually, after four months of negotiating, the governments of the Allied countries, such as the British Labour Prime Minister Lloyd George, refused to issue passports to those who wanted to travel to Stockholm. As of August 1917 it was clear that the Stockholm Conference would never take place.
Behind all those "small scale" discussions, world historical developments played a role. When the tide of the battle turned, so too did the standpoints in Stockholm. The attitude of the British Labour government - reserved at first, sympathetic later on, and uncooperative at the end - may be traced to its assessment of the possibilities of a separate German-Russian peace treaty. As time went on and Lenin perceived greater horizons for the Bolsheviks, he was less inclined to invest his energy in the Second International's success. The conflicts of 1917 show many similarities to those in our times: questions of autonomy and ethnicity, the position of Turkey within Europe, and Western intervention in Iran. The tricks and shadow-boxing of the negotiators in the socialist camp also seem familiar. Some of them came to power after the war. In spite of the project's failure, the participants' motives and behavior are very worth studying.