Individuals "die" what is called a natural death; 
ideological and political trends, however, cannot 
die in that way. Just as the bourgeoisie will not 
die until it is overthrown, a trend nurtured and 
supported by the bourgeoisie, and expressing the 
interests of a small group of intellectuals and 
members of the labour aristocracy that have joined 
hands  with the bourgeoisie, will not die unless 
it is "killed", i.e., overthrown, deprived of all 
influence on the socialist proletariat. This trend 
is strong in its links with the bourgeoisie. 
Because of the objective conditions of the 
"peaceful" period of 1871-1914, it has become a 
kind of commanding, parasitic stratum in the 
working-class movement.

In such conditions, it is our duty, not only to 
"blame," but to ring the tocsin, ruthlessly 
unmask, overthrow, and oust this parasitic stratum 
from their posts, and destroy their "unity" with 
the working-class movement, because such 
"unity" means, in practice, unity of the 
proletariat with the national bourgeoisie and a 
split in the international proletariat, the unity 
of lackeys and a split among the revolutionaries.

"Intransigence is a force," Golay says with 
justice; he demands that "the socialism that must 
be reborn" should be intransigent. But is it not 
all the same to the bourgeoisie whether the 
proletariat practises reconciliation with it 
directly, or indirectly through bourgeois 
adherents, defenders, and agents within the 
working-class movement, i.e., through the 
opportunists? The latter is even more advantageous 
to the bourgeoisie, because it secures for it a 
stronger influence over the workers.

Golay is a thousand times right when he says that 
there is a socialism that is dying and a socialism 
that must be reborn; this death and this rebirth, 
however, comprise a ruthless struggle against the 
trend of opportunism—-not merely an ideological 
struggle, but the removal of that hideous 
excrescence from the body of the working-class 
parties, the expulsion from those organisations of 
certain representatives of this tactic, which is 
alien to the proletariat, a definite break with 
them. They will die neither physically nor 
politically, but the workers will break with them, 
will throw them into the cesspool of the servitors 
of the bourgeoisie. The example of their 
corruption will educate a new generation, or, more 
correctly, new proletarian armies capable of an 
uprising.

--V.I. Lenin, "The Voice of an Honest French Socialist"
1915