On June 19, 1953, Julius and Ethel Rosenberg died in the electric chair at Sing Sing prison in New York State. They remain the only Americans executed for espionage during peacetime. Their sons, ages 6 and 10 at the time, remain the only American citizens to have both their parents put to death by capital punishment. Today, Robert Meeropol, 62, is an outspoken opponent of the death penalty and the founder of the Rosenberg Fund for Children.

In its nearly 20 year existence, the Rosenberg Fund for Children has donated more than 3.5 million dollars for the educational and emotional support of the children of progressive activists who find themselves in legal trouble.

Robert was 3 years old and his brother was 7 in 1950 when their parents were arrested. World War II had been over for 5 years, but military and political tensions in the post-war years had given rise to a new conflict—the Cold War. The US and much of the Western World had grown deeply distrustful of their former ally, the Soviet Union—which had startled the world by producing its own atomic weapon in 1949, giving rise to a fear the Soviets would one day use the weapon against the United States. In February of 1950, Senator Joseph McCarthy dramatically raised the level of concern by announcing known Communists were working for the US State Department. That summer the Rosenbergs were arrested.

The trial of the Rosenbergs began in March, 1951. The star witness for the government was Ethel Rosenberg’s brother, David Greenglass, who admitted to spying for the Soviet Union during World War II and implicated his sister, her husband, and his own wife, Ruth. He cooperated with the prosecution, and in return, according to a 2003 interview he gave to CBS News, his wife was never indicted. He served only 10 years in prison.

Ruth and David Greenglass were the only witnesses to testify against Ethel Rosenberg.

What was it like being the children of Julius and Ethel Rosenberg?

Our parents were accused of the most terrible crime of the Cold War—giving the Soviet Union the secret to the atomic bomb. It was like if Osama bin Laden were brought to the United States and put on trial today—that’s how angry people were. We were in a very scary situation. I don’t remember a whole lot, but I do remember the constant state of anxiety. Something terrible had happened and my parents had been taken away, and I had to be really careful or they—I didn’t know who they were, but I knew they were powerful—might come and get me also.

What was the charge against your parents?

Everyone thinks they were charged and convicted of treason. But treason is defined in the Constitution, and one of the elements is aiding the enemy. My parents were accused of aiding the Soviet Union when we were allied with them in World War II. So instead the government charged them with conspiracy to commit espionage. They were not even charged with espionage itself.

In order to be convicted of conspiracy, the government has to prove that two or more people got together and planned to do something, and took at least one act to further the plan. When you talk about planning a crime, you don’t have to have much physical evidence—in fact in my parents’ case there was no physical evidence. There were two executions solely based upon the oral testimony of people who say they were also involved in a conspiracy, and in exchange for their testimony received more lenient treatment. That strikes a lot of people, when they really think about it, as a really bad set of circumstances under which to subject someone to capital punishment.

What happened to you and your brother when your parents were arrested?

We were sent to my mother’s mother’s house. My grandmother wanted Ethel to turn on her husband and spare her brother, and to put pressure on her, she left us at a shelter. I have no memory of ever seeing her after that. When my father’s mother, who had been ill, was well enough to take us, we lived with her. But my brother was in the New York City public schools and receiving a great deal of harassment, and we were sent to live with acquaintances of my parents in New Jersey. We were not taken in by other relatives because they were all afraid.

Did you see your parents after they were arrested?

For a year we didn’t. There was the hope that they would win their trial and be released and we would never have to see them in prison. Beginning in the fall of 1951 we started visiting them. I can’t remember how many times we saw them, probably a dozen times over the next year and a half. In fact, if I hadn’t visited them in prison, I would have virtually no memories of them at all.

In 1954 Robert and Michael were adopted by Able and Anne Meeropol, supporters of the Rosenbergs. The boys changed their last name to Meeropol and dropped out of public sight.

What are your concerns for children who have a parent facing execution?

There are lots of statistics on the demographics of death row, but one of the pieces of information that is sorely missing—what no one has bothered to compile as far as I know—is how many people on death row have immediate family members who are children? The children are innocent, and if their loved ones are executed, they become just collateral damage. And what happens to them in the long run and what is the impact on society? Legislators who favor capital punishment should address this issue and should make sure that they are not, in the process of supporting capital punishment, actually causing more harm than good.

Robert Meeropol now believes that his father was guilty of a crime: aiding the Soviets in the 1940s. He does not believe he was guilty of passing secrets about the atomic bomb—the basis for the charge which delivered him to the electric chair. As for his mother, Robert suspects, as the trial date neared, his uncle and aunt were pressured by the government to implicate her. The only allegation made against Ethel Rosenberg was that she typed up notes to be passed to the Soviets—an allegation which David Greenglass recanted in 2001.

What is your view of the case against your parents now that more than 50 years has gone by?

I think the evidence is now pretty clear that my father did help the Soviet Union with non-atomic information during World War II, and the government took that and blew it out of proportion to make a political point. My mother was arrested in attempt to coerce my father into confessing and implicating others, which my parents both refused to do. Last year the grand jury testimony of Ruth Greenglass was released and there was no mention of my mother. When you really study the case, the only reasonable conclusion is that Ethel Rosenberg was not guilty.

How has your experience as one of two people to have both parents executed by the US government shaped your view of probability?

There is an inseparable relationship between probability and certainty. I grew up being absolutely certain of my parents’ complete and total innocence. And I learned over a 40-year period that reality was a little more complicated than that. Things that I thought were 100% certain were not 100% certain. That reality is nuanced and subtle and filled with probabilities and possibilities as opposed to certainties.

That is one of the problems with capital punishment. It requires perfection, and perfection requires complete certainty. Human beings are incapable of such perfection and human systems are incapable. And if we have a small, even infinitesimal probability of failure, an innocent person will be executed.