Yes, They Were Guilty. But of What Exactly? June 15, 2003 By SAM ROBERTS Fifty years ago Thursday, Julius and Ethel Rosenberg were executed in the electric chair at Sing Sing. Their execution, originally set for 11 p.m. on Friday, June 19, 1953, was rescheduled for 8 p.m. to avoid conflict with the Jewish sabbath. "They were to be killed more quickly than planned," the playwright Arthur Miller wrote, "to avoid any shadow of bad taste." A shadow lingers. "I grew up believing Ethel and Julius were completely innocent," Robert Meeropol, who was 6 years old in 1953, says of the Rosenbergs, his parents. "By the time I completed law school in 1985, however, I realized that the evidence we had amassed did not actually prove my parents' innocence but rather only demonstrated that they had been framed." After digesting newly released American decryptions of Soviet cables a decade later, Mr. Meeropol came to a revised conclusion. "While the transcriptions seemed inconclusive, they forced me to accept the possibility that my father had participated in an illegal and covert effort to help the Soviet Union defeat the Nazis," he writes in his new memoir, "An Execution in the Family: One Son's Journey" (St. Martin's Press). Of course, the Rosenbergs weren't executed for helping the Soviets defeat the Nazis, but as atom spies for helping Stalin end America's brief nuclear monopoly. They weren't charged with treason (the Russians were technically an ally in the mid-1940's) or even with actual spying. Rather, they were accused of conspiracy to commit espionage - including enlisting Ethel's brother, David Greenglass, through his wife, Ruth, to steal atomic secrets from the Los Alamos weapons laboratory where he was stationed as an Army machinist during World War II. Mr. Greenglass's chief contribution was to corroborate what the Soviets had already gleaned from other spies, which by 1949 enabled them to replicate the bomb dropped on Nagasaki. (He confessed, testified against his sister and brother-in-law and was imprisoned for 10 years; Ruth testified, too, and was spared prosecution.) As leverage against Julius, Ethel was also indicted on what, in retrospect, appears to have been flimsy evidence. The government didn't have to prove that anything of value was delivered to the Soviets, only that the participants acted to advance their goal. "When you're dealing with a conspiracy, you don't have to be the kingpin, you have to participate," says James Kilsheimer, who helped prosecute the Rosenbergs. "You can't be partially guilty any more than you can be partially pregnant." But to justify the death penalty, which was invoked to press the Rosenbergs to confess and implicate others, the government left the impression that the couple had handed America's mightiest weapon to the Soviets and precipitated the Korean War. Records of the grand jury that voted the indictment remain sealed. But we now know the Soviet cables decoded before the trial provided no hard evidence of Ethel's complicity. And Mr. Greenglass has recently admitted that he lied about the most incriminating evidence against his sister. The government's strategy backfired. Ethel wouldn't budge. The Rosenbergs refused to confess and were convicted. "She called our bluff," William P. Rogers, the deputy attorney general at the time, said shortly before he died in 2001. "They had the key to the death chamber in their hands," Mr. Kilsheimer says. "They never used it." Whatever military and technical secrets Julius delivered to the Russians - and it now seems all but certain that, as a committed Communist, he did provide information - the Rosenbergs proved more valuable as martyrs than as spies. "The Soviets did win the propaganda war," said Robert J. Lamphere, an agent for the Federal Bureau of Investigation. The war isn't over. David Greenglass is 81; Ruth Greenglass is 79. They live under a pseudonym because their surname has become synonymous with betrayal of kin and country. "Perhaps," Mr. Meeropol says, "this is David and Ruth's final punishment." On Thursday, Mr. Meeropol, who is 56, and his brother Michael, who is 60, (they took their adoptive parents' name) will attend a program at City Center in Manhattan to "commemorate the Rosenbergs' resistance" and benefit the Rosenberg Fund for Children, which Robert runs. Michael Meeropol is chairman of the economics department at Western New England College. Would any evidence ever convince him that his father was a spy? "If Soviet documents were verified as historically accurate, I'd certainly believe that," he replied. Then what? How would he explain his father's behavior? "I would have to do some thinking about my parents being involved in dangerous things, but I can't judge people from the 1940's," he said. "He's not in the Army. He has bad eyesight. He can't make the contribution that others were making. I could argue that this was a way of doing it." To this day, plenty of people would argue that he's wrong. Sam Roberts, the deputy editor of the Week in Review, is the author of "The Brother: The Untold Story of the Rosenberg Case." Copyright 2003 The New York Times Company