 Complete the following phrase:  In 1928, Stalin declared that class war between the proletariat and their enemies would intensify as socialism developed. He warned of a danger from the right, including in the Communist Party itself. The first major show trial in the USSR was the Shakhty Trial of 1928, in which several middle-class industrial specialists were convicted of sabotage. From 1929 to 1930, further show trials were held to intimidate opposition: these included the 