So it's materially possible to establish communism in Sudan or Afghanistan?
The reason Marx, Engels, Lenin, Trotsky and other Marxists do not believe that socialism can be built in one backward or even one advanced nation is because the material conditions for it do not, and cannot, exist in any single nation.
Socialism as a historical stage is based on material conditions higher than the most advanced capitalist society can muster. Since capitalism itself requires a global system to achieve that degree of development, it would be pretty odd to suggest that socialism can achieve it in a single nation, in isolation from the rest of the world.
Socialism is an international movement for that reason.
An historical example; the USSR tried to build socialism and claimed it had actually done so at some point. Yet it always lacked behind the most advanced capitalist countries, and eventually fell due to internal contradictions and some other factors.
If a nation such as the USSR could not "do it by itself", while controlling an industrialized society comprising a huge landmass, then neither can...Nepal.
I think he may have meant socialism . Socialism can be established in one nation . However it cannot survive isolated in one nation .
"Marxist psychology is not a school amidst schools, but the only genuine psychology as a science. A psychology other than this cannot exist. And the other way around: everything that was and is genuinely scientific belongs to Marxist psychology" -Lev Vygotsky
"The Bolsheviks have shown that they are capable of everything that a genuine revolutionary party can contribute within the limits of historical possibilities. They are not supposed to perform miracles. For a model and faultless proletarian revolution in an isolated land, exhausted by world war, strangled by imperialism, betrayed by the international proletariat, would be a miracle."
-Rosa Luxemburg