From 1945 to 1989, the world was divided into two massively armed imperialist blocs: the USA and the USSR. Under these conditions, the critical question facing the working class was that of the balance of forces in the class struggle: would the working class be sufficiently strong to push back the threat of war, and impose its own solution to the crisis. With the collapse of the Eastern bloc in 1989, the danger of imperialist world war receded, but this can offer no comfort to the working class: if it fails to overthrow capitalism and establish society on a new basis, then there is a real danger that the whole of human society will collapse into a generalised decomposition, of which the ongoing environmental catastrophe we see around us is a part.