Although the Cossacks were sometimes portrayed by Bolsheviks and, later, émigré historians, as a monolithic counterrevolutionary group during the civil war, there were many Cossacks who fought with the Red Army throughout the conflict. Many poorer Cossack communities also remained susceptible to communist propaganda. In late 1918 and early 1919, widespread desertion and defection among Don, Ural, and Orenburg Cossacks fighting with the Whites produced a military crisis that was exploited by the Red Army in those sectors. After the main White armies were defeated in early 1920, many Cossack soldiers switched their allegiance to the Bolsheviks, and fought with the Red Army against the Poles and in other operations.