On 31 August 1919 John Reed, Benjamin Gitlow, and a group of pro-Bolshevik delegates who had been ejected from the national convention of the Socialist Party founded the Communist Labor Party. The next day, Charles Ruthenberg and Louis Fraina, joined by left-wing Socialists and other radicals who had boycotted the Socialist Party convention, created the Communist Party of America. Both parties announced their loyalty to the principles of the Bolshevik Revolution and to the leadership of the newly formed Communist International.
     
      Two American Communist parties were one too many, and the Comintern ordered the two to merge. In January 1920 Grigory Zinoviev, head of the Comintern, dispatched a courier to America with written instructions demanding that the parties unite and giving guidance for the organizational structure of the new party. A supplemental order even specified the name: United Communist Party. The courier was arrested and his papers confiscated as he was trying to cross Latvia. But the Latvian government released the messages to the press, and they were effectively delivered when the New York World published them.

     In the United States, both Communist parties promised obedience to the Comintern, but personal and organizational rivalries were so intense that the union was repeatedly delayed, as various factions maneuvered for supremacy. So bitter was the in-fighting that the Communist Party of America, the larger of the two original parties, split into two more groups, each of which claimed the name Communist Party of America. One of the splinter groups, led by Ruthenberg and Jay Lovestone, proceeded to merge with the Communist Labor Party in 1920 under the name United Communist Party. This new party, however, was no larger than the remaining Communist Party of America, which, under the leadership of Nicholas I. Hourwich and Alexander Bittelman, continued to be its hostile rival. There were still two American Communist parties.

     The Communist International was planning to hold its third congress in June 1921. It did not want the occasion to be marred by the presence of competing American delegations. Therefore, in the spring of 1921 the Executive Committee of the Communist International (ECCI) issued an ultimatum to American Communists, demanding that they settle their differences. Document I is the actual text of this ultimatum. Note that it is not a plea for unity; rather, it is a blunt assertion of the supremacy of the Comintern, containing the declaration that further delay constitutes a "crime against the Communist International" and that the American failure to achieve unity is an "injury of the authority of the Communist International." To press the point, the Comintern threatens to deny both groups representation at the congress and actually voids their representation in the ECCI until they achieve unity.