Quoting from the Wikipedia article (I know there are more professional sources) "Julius and Ethel Rosenberg were American citizens who were convicted of spying on behalf of the Soviet Union. The couple was accused of providing top-secret information about radar, sonar, jet propulsion engines, and valuable nuclear weapon designs; at that time the United States was the only country in the world with nuclear weapons. Convicted of espionage in 1951, they were executed by the federal government of the United States in 1953 in the Sing Sing correctional facility in Ossining, New York."
During the sessions for the 1983 album Infidels Bob Dylan recorded the song shown above, but it was never released legitimately, It was on some illegal bootleg records.
I highly recommend my readers who are Dylan fans get this book:
“Surviving in a Ruthless World: Bob Dylan’s Voyage to Infidels” by Terry A. Gans. I got the Kindle version on Amazon.com and am currently reading it. Each chapter is devoted to a song recorded in the Infidels sessions in Spring 1983. I had a lot of fun reading a chapter and then listening to the recording.
I also suggest reading this article from Rolling Stone Magazine.