Prosecutions
Original plans for Bentley to serve as a double agent and gather sufficient evidence to prosecute the Soviet agents identified in the Silvermaster files were ruined when her identity was inadvertently leaked and the USSR quickly shut down its operations in order to avoid embarrassing and damaging prosecutions. The Silvermaster file in combination with other secret proofs such as the Venona intercepts gave US intelligence the identity of many Soviet agents without the practical means to secure convictions. Also, the statute of limitations for an espionage prosecution was quite short. This was a significant part of the backstory of McCarthyism. Bentley's double agent career would have enabled the US to expose the spies without compromising Venona and losing that as an ongoing intelligence source.
Read more about this topic: FBI Silvermaster File