V. I. Lenin
Collected Works
New York: 1930, Excerpted in International Communism in the Era of Lenin:
A Documentary History by Helmut Gruber
New York: Fawcett World Library, 1967, p. 59

"On the Tasks of Revolutionary Social Democracy in the European War"

"The conduct of the leaders of the German Social Democratic party, the
strongest and most influential party belonging to the Second International
(1889-1914), which voted for the military appropriations and which
repeated the bourgeois chauvinist phrases of the Prussian Junkers and the
bourgeoisie, is a direct betrayal of socialism. Under no circumstances,
even assuming the absolute weakness of the party and the necessity of
its submitting to the will of the bourgeois majority of the nation,
can the conduct of the leaders of the German Social Democratic party be
justified. This party has in fact adopted a national-liberal policy."