What's more plausible, the Soviets actually succeeded at such a complex project, and the US government suppressed it so effectively that after the collapse of t

What's more plausible, the Soviets actually succeeded at such a complex project, and the US government suppressed it so effectively that after the collapse of the Soviet Union there was no evidence left whatsoever. ...or the whole thing was just propaganda in the first place (either Soviet to try claim weird science skills, or US to try claim the Soviets are crazy)?