The quote
"A chain is only as strong as its weakest link" is attributed to V. I.
Lenin who was discussing his reasons why the
Bolsheviks were agitating the
Russian
Proletariat before the
Revolution of 1917
(in "What Is To Be Done?" I think).
Traditional
Marxist thought held that places like
Britain and
Germany would be most likely to undergo a
Socialist Revolution because the
working classes in those countries were larger, better educated and more politically aware.
Lenin argued that although
Russia till had an
agrarian/
peasant based economy and its working class was small and centred around the cities, because its
government (the autocracy of Nicholas II) was so much weaker than that of the other capitalist countries, a
well motivated vanguard could create a revolution more quickly than anywhere else.
It is this principle that forms the basis of
Bolshevism.