Complex sentence: By the mid to late 1920s, there were three elements of Soviet power operating in the United States, despite the absence of formal diplomatic relations, the Comintern, military intelligence or GRU, and the forerunner of the KGB, the GPU.
Split into simpler sentences: By the mid to late 1920s, there were three elements of Soviet power operating in the United States, despite the absence of formal diplomatic relations. They were the Comintern, military intelligence or GRU, and the forerunnerof the KGB, the GPU.