The Second International was established in July 1889, on the centenary of the fall of the Bastille, and gathered together the Social Democratic parties worldwide. It represented a high point of working class internationalism and was founded on the principles of world socialism. More importantly, the Socialist International formally adhered to the ideas of Marxism.
However, the Socialist International had been born in a period of upswing of capitalism. The tops of the movement came under the pressures of capitalism, which had a deeply corrosive effect, pushing the leadership in an increasingly reformist direction. While the leaders of the trade unions and the party began to accommodate themselves to the day-to-day struggle over reforms, the socialist revolution was put off into the distant future. These alien pressures began to reflect themselves through class compromise and adaption. The top layers in the unions and in parliament, raising themselves above the masses, increasingly adapted themselves to this new environment. While espousing the “dictatorship of the proletariat” and “proletarian internationalism” in words, in practice they had gone over to the nation state and reformism. It would, however, take great events, namely world war, to expose this fact.