Very early on, John conflates "senseless mass slaughter" with opposition to "a tyrannical fascist world," and says "we can't know" what might have happened using "well-organised non-violent opposition alone."
This is sheer bourgeois idealism. The Soviet Union made strenuous efforts, and well-reasoned arguments, for collective security years before WWII began.
The Bolshevik revolution - born out of opposition to war - was peaceful until reactionaries tried to restore capitalism.
All progressive revolutions have eventually had to defend themselves with force of arms - they have had no choice.
To cite the Cuban experience is disingenuous. Che and Fidel saw in Guatemala in 1954 the overthrow of a democratically elected government by force of US arms.
They drew conclusions that safeguarded the Cuban people's progress.
No appeals to "fairness" could have defended Cuba from the US-backed Bay of Pigs invasion.
In the following year, another likely invasion by the US was stymied by the installation of the only thing imperialism understood: some extremely potent artillery.
The history of all progressive revolutions, from Mossadegh's Iran to Allende's Chile and republican Spain has regrettably taught us that all progressive, people-orientated developments must be defended.
The choice between violence and non-violence is not ours to make, however just may be our demands.
Roger Fletcher
Chesham