“The opportunist, by his very nature, tends to avoid a definite and final solution of a question; he is always seeking for alternatives; he writhes like an eel between mutually exclusive points of view; he tries to ‘be in agreement’ with all sides, but expresses his disagreements in amendments, doubts, pious and innocent wishes, etc. etc.”
— One Step Forward, Two Steps Back, 1904
“In the past, before the war, opportunism was often looked upon as a legitimate, though ‘deviationist’ and ‘extremist,’ component of the Social-Democratic Party. The war has shown the impossibility of this in the future. Opportunism has ‘matured,’ and is now playing to the full its role as emissary of the bourgeoisie in the working-class movement. Unity with the opportunists has become sheer hypocrisy, exemplified by the German Social-Democratic Party.
On every important occasion (e.g., the August 4 vote), the opportunists present an ultimatum, to which they give effect through their numerous links with the bourgeoisie, their majority on the executives of the trade unions, etc. Today unity with the opportunists actually means subordinating the working class to their ‘own’ national bourgeoisie, and an alliance with the latter for the purpose of oppressing other nations and of fighting for dominant-nation privileges; it means splitting the revolutionary proletariat of all countries.”
— Socialism and War, 1915