Comintern
The Comintern (Communist International) was a international political front organization led by the USSR.
Platform
History
The Second International splintered in 1916 as factions disagreed with how to address World War 1. The Labour Party in the UK and SDP in Germany supported the war. There was significant advocacy for pacifism, but few presented a platform to actually oppose war. Lenin in particular advocated for taking advantage of Russia's possible defeat in the war for a socialist revolution.
Following the October Revolution, Lenin assisted Kun with a socialist revolution in Hungary.
Stalin dissolved Comintern in 1943, under pressure from the Allies.
Cominform was the eventual successor organization.