[2][3][4][5] Other convicted co-conspirators were sentenced to prison, including Ethel's brother, David Greenglass (who had made a plea agreement), Harry Gold, and Morton Sobell.

[6][7] For decades, many people, including the Rosenbergs' sons (Michael and Robert Meeropol), have maintained that Ethel was innocent of spying and have sought an exoneration on her behalf from multiple U.S.

[9] Freedom of Information Act (FOIA) requests filed about the Rosenbergs and the legal case against them have resulted in additional U.S. government records being made public, including formerly classified materials from U.S. intelligence agencies.

Important research on electronics, communications, radar and guided missile controls was undertaken at Fort Monmouth during World War II.

[12] According to a 2001 book by his former handler Alexander Feklisov, Rosenberg was originally recruited to spy for the interior ministry of the Soviet Union, NKVD, on Labor Day 1942 by a former spymaster Semyon Semyonov.

[13] By this time, following the invasion by Nazi Germany in June 1941, the Soviet Union had become an ally of the Western powers, which included the United States after the attack on Pearl Harbor.

Under Feklisov's supervision, Rosenberg recruited sympathetic individuals into NKVD service, including Joel Barr, Alfred Sarant, William Perl, and Morton Sobell, also an engineer.

[14] Perl supplied Feklisov, under Rosenberg's direction, with thousands of documents from the National Advisory Committee for Aeronautics, including a complete set of design and production drawings for Lockheed's P-80 Shooting Star, the first U.S. operational jet fighter.

Feklisov learned through Rosenberg that Ethel's brother David was working on the top-secret Manhattan Project at the Los Alamos National Laboratory; he directed Julius to recruit Greenglass.

[13] In February 1944, Rosenberg succeeded in recruiting a second source of Manhattan Project information, engineer Russell McNutt, who worked on designs for the plants at Oak Ridge National Laboratory.

[17] However, Lavrentiy Beria, the head official of the Soviet nuclear project, used foreign intelligence only as a third-party check rather than giving it directly to the design teams, who he did not clear to know about the espionage efforts, and the development was indigenous.

Considering that the pace of the Soviet program was set primarily by the amount of uranium that it could procure, it is difficult for scholars to judge accurately how much time was saved, if any.

[18] In January 1950, the U.S. discovered that Klaus Fuchs, a German refugee and theoretical physicist working for the British mission in the Manhattan Project, had given key documents to the Soviets throughout the war.

[23][24] The U.S. government claimed Sobell was arrested by the Mexican police for bank robbery on August 16, 1950, and he was extradited the next day to the United States in Laredo, Texas.

Gordon Dean, the chairman of the Atomic Energy Commission, said: "It looks as though Rosenberg is the kingpin of a very large ring, and if there is any way of breaking him by having the shadow of a death penalty over him, we want to do it."

[35] In imposing the death penalty, Kaufman observed that he held the Rosenbergs responsible not only for espionage but for American deaths in the Korean War:[36] I believe your conduct in putting into the hands of the Russians the A-bomb years before our best scientists predicted Russia would perfect the bomb has already caused, in my opinion, the Communist aggression in Korea, with the resultant casualties exceeding 50,000 and who knows but that millions more of innocent people may pay the price of your treason.

The Rosenbergs made a public statement: "By asking us to repudiate the truth of our innocence, the government admits its own doubts concerning our guilt... we will not be coerced, even under pain of death, to bear false witness.

[45][46] Defense of the Rosenbergs surged in November and December 1952 and was organized by the Communist Party of the Soviet Union[47]—confirmation of which occurred with the publication of KGB documents obtained by Alexander Vassiliev in 2011.

[49] According to American historian Ronald Radosh, the Soviet Union's goal was "to deflect the world's attention from the sordid execution of the innocent [Jewish Slánský trial defendants] in Soviet-controlled Czechoslovakia.

Mr. Bloch [their counsel], who delivered one of the main orations, bitterly exclaimed that America was "living under the heel of a military dictator garbed in civilian attire": the Rosenbergs were "Sweet.

"[61] Boris V. Brokhovich, the engineer who later became director of Chelyabinsk-40, the plutonium production reactor and extraction facility that the Soviet Union used to create its first bomb material, alleged that Khrushchev was a "silly fool".

"[64] General Leslie Groves, who developed the American nuclear program as part of the Manhattan Project, said during a United States Atomic Energy Commission hearing on Robert Oppenheimer that he thought that "the data that went out in the case of the Rosenbergs was of minor value", and that he "always felt the effects were greatly exaggerated, that the Russians did not get too much information out of it".

[67] The Venona messages did not feature in the Rosenbergs' trial, which relied instead on testimony from their collaborators, but they heavily informed the U.S. government's overall approach to investigating and prosecuting domestic communists.

[68] In 1995, the U.S. government made public many documents decoded by the Venona project, showing Julius Rosenberg's role as part of a productive ring of spies.

Deputy Attorney General of the United States William P. Rogers, who had been part of the prosecution of the Rosenbergs, discussed their strategy at the time in relation to seeking the death sentence for Ethel.

"[77] Sobell said that he thought the hand-drawn diagrams and other atomic-bomb details acquired by Greenglass and passed to Julius were of "little value" to the Soviet Union and were used only to corroborate what they had learned from the other atomic spies.

[71][72] According to Vassiliev, Julius and Ethel worked personally with KGB agents who were given the codenames Twain and Callistratus, and were also described as being the ones who recruited Greenglass and McNutt for the Manhattan Project spy mission.

[80][26] After Sobell's 2008 confession, they acknowledged their father had been involved in espionage but that in their view the case was riddled with prosecutorial and judicial misconduct, that their mother was convicted on flimsy evidence to place leverage on her husband, and that neither deserved the death penalty.

[83][26] In 2015, following the most recent grand jury transcript release, Michael and Robert Meeropol called on U.S. President Barack Obama's administration to acknowledge that Ethel Rosenberg's conviction and execution was wrongful and to issue a proclamation exonerating her, though her innocence is still not proven.

[26][89] As of June 2023[update] Michael and Robert were requesting Director of National Intelligence Avril Haines to release the records related to their mother's case,[90] per a 2009 executive order.