As is well known, the Soviet system under Stalin confected countless false reports of sabotage, insurrection, and things of a like kind. It also committed innumerable acts of oppression and violence against the people of the Soviet Union.
However, there were some genuine attacks against the Soviet state, which were not just fabrications or false-flag operations. Is there any evidence these were helped by foreign-based organisations, such as the 4th international, or foreign powers?
In the words of the undervalued author Melvin Burgess, torture reduces the best of us to so much mindless gobshite. For this reason, confessions by people Stalin blamed don't count as evidence. Evidence emanating from outside the Soviet Union (letters planning attacks, etc) would count.
I am excluding Axis powers during world war 2, as imho this was an inevitable part of the war, not a separate phenomenon. I chose the year 1928 because I don't want to get tangled up with long tail of the Russian Civil War.
I'm interested to know if Stalin's accusations against the Mensheviks, Trotskyists, Bukharinites and so on had any foundation. As well as the assassination attempts I posted above, there were the partisans after world 2, the Basmachi rebels opposed to collectivisation, and so on.
There were, in short, a lot of people who had good cause to hate the Soviet rulers in this period. It would be interesting to know if there were any crumbs of truth in the ravings and outpourings of the Soviet propaganda machine.