Tell me more about this spy ring. I know about the Rosenbergs, but what was their motivation? Was it money? Ideals? How did they have access to so many nuclear secrets. I know their children went to clear their name decades later and instead discovered they were guilty as charged.
The world would’ve been a much different place if the Russians had to wait 5-10 more years to get nuclear weapons. Maybe.
Klaus Fuchs was the son of a Lutheran pastor (he later became a Quaker) in Germany who joined the Social-Democrat party, got expelled from it, and joined the Communist party. He fled Germany after the 1933 Reichstag fire and ended up in the UK, where he earned two doctorates in physics. He joined Tube Alloys, the British atomic program as a theoretical physicist. By 1942, he was passing secrets to the Soviets. When Tube Alloys got rolled up into the American Manhattan Project, he was assigned to the bomb-development laboratory at Los Alamos, NM, under Robert Oppenheimer. And he continued to pass information to the Soviets.
I need to interject something here. In Great Depression America, free-market capitalism was in disrepute, blamed for the Wall Street crash and for the depression itself. Socialism, Communism, and Fascism were competing to be the wave of the future. Many decent, seemingly intelligent, Americans bought into those ideologies. American poet Ezra Pound embraced Mussolini's fascist system and moved to Italy. A raft of American writers, actors, musicians, etc., either sympathized with or outright joined the Communist Party USA. Communism is presented as genuine Americanism in this pamphlet.

The USSR was actively recruiting American communists to help with the war effort. They emphasized that the Soviet Union was an ally, that they were all in it together to beat the Nazis.
So, among the hundreds, maybe even thousands, of Americans who did their part to help the embattled Soviet Union were Julius and Ethel Rosenberg and Ethel's brother David Greenglass. Julius Rosenberg joined the Army and worked at the Signal Corps Engineering Laboratories at Fort Monmouth, NJ, in 1940, where he worked as an engineer-inspector until 1945. The Monmouth Labs did important research on electronics, communications, radar and guided missile controls. Among the companies contracted to develop and produce war materiel based on Monmouth research was Emerson Radio. Julius passed copious amounts of highly classified information, including a complete proximity fuse, to the Soviets. Ethel was not an active spy herself. She basically organized Julius' paperwork.
The Soviet agent running Julius Rosenberg learned that Ethel's brother David Greenglass was working at the Los Alamos lab, and through her, Greenglass was recruited.
Fuchs confessed in 1950 and spent 9 years in prison in Britain. After his release, he emigrated to East Germany and worked there.
Greenglass also confessed in 1950, and implicated his brother-in-law, Julius Rosenberg. He served 9-1/2 years in prison.
The Rosenbergs stuck to their claims of innocence. Ethel--who was a small fish compared to the others--was prosecuted as a lever to make Julius talk, but it failed. Julius could have saved Ethel by confessing, but they both staunchly maintained their innocence right up to their executions on 19 June 1953.
As for motives--who knows? Misguided patriotism, communist ideals, money, maybe a combination of them?
Many historians don't believe that the information obtained from Fuchs and Greenglass provided much direct assistance to the Soviet atomic-bomb project. The Soviet scientists never had access to it. The non-scientist overseeing the project used the information as a check on what his own scientists were telling him. His knowledge probably saved some time by steering the Soviet physicists away from dead ends.