Stalin's regime forcibly purged society of what it saw as threats to itself and its brand of communism (so-called "enemies of the people"), which included political dissidents, non-Soviet nationalists, the bourgeoisie, better-off peasants ("kulaks"), and those of the working class who demonstrated "counter-revolutionary" sympathies. This resulted in mass repression of such people as well as their families, including mass arrests, show trials, executions, and imprisonment in forced labor and concentration camps known as gulags. The most notable examples of this were the Great Purge and the Dekulakization campaign. Stalinism was also marked by mass religious persecution, and ethnic cleansing through forced deportations. Some historians such as Robert Service have blamed Stalinist policies, particularly the collectivization policies, for causing famines such as the Holodomor. Other historians and scholars disagree on the role of Stalinism.