Julius and Ethel Rosenberg were executed 55 years ago, on June 19, 1953. But last week, they were back in the headlines when Morton Sobell, the co-defendant in their famous espionage trial, finally admitted that he and his friend, Julius, had both been Soviet agents.

It was a stunning admission; Sobell, now 91 years old, had adamantly maintained his innocence for more than half a century. After his comments were published, even the Rosenbergs’ children, Robert and Michael Meeropol, were left with little hope to hang on to -- and this week, in comments unlike any they’ve made previously, the brothers acknowledged having reached the difficult conclusion that their father was, indeed, a spy. “I don’t have any reason to doubt Morty,” Michael Meeropol told Sam Roberts of the New York Times.

With these latest events, the end has arrived for the legions of the American left wing that have argued relentlessly for more than half a century that the Rosenbergs were victims, framed by a hostile, fear-mongering U.S. government. Since the couple’s trial, the left has portrayed them as martyrs for civil liberties, righteous dissenters whose chief crime was to express their constitutionally protected political beliefs. In the end, the left has argued, the two communists were put to death not for spying but for their unpopular opinions, at a time when the Truman and Eisenhower administrations were seeking to stem opposition to their anti-Soviet foreign policy during the Cold War.

To this day, this received wisdom permeates our educational system. A recent study by historian Larry Schweikart of the University of Dayton has found that very few college history textbooks say simply that the Rosenbergs were guilty; according to Schweikart, most either state that the couple were innocent or that the trial was “controversial,” or they “excuse what [the Rosenbergs] did by saying, ‘It wasn’t that bad. What they provided wasn’t important.’ ”

Indeed, Columbia University professor Eric Foner once wrote that the Rosenbergs were prosecuted out of a “determined effort to root out dissent,” part of a broader pattern of “shattered careers and suppressed civil liberties.” In other words, it was part of the postwar McCarthyite “witch hunt.”

But, in fact, Schweikart is right, and Foner is wrong. The Rosenbergs were Soviet spies, and not minor ones either. Not only did they try their best to give the Soviets top atomic secrets from the Manhattan Project, they succeeded in handing over top military data on sonar and on radar that was used by the Russians to shoot down American planes in the Korean and Vietnam wars. That’s long been known, and Sobell confirmed it again last week.

To many Americans, Cold War espionage cases like the Rosenberg and Alger Hiss cases that once riveted the country seem irrelevant today, something out of the distant past. But they’re not irrelevant. They’re a crucial part of the ongoing dispute between right and left in this country. For the left, it has long been an article of faith that these prosecutions showed the essentially repressive nature of the U.S. government. Even as the guilt of the accused has become more and more clear (especially since the fall of the Soviet Union and the release of reams of historical Cold War documents), these “anti anti-communists” of the intellectual left have continued to argue that the prosecutions were overzealous, or that the crimes were minor, or that the punishments were disproportionate.

The left has consistently defended spies such as Hiss, the Rosenbergs and Sobell as victims of contrived frame-ups. Because a demagogue like Sen. Joseph McCarthy cast a wide swath with indiscriminate attacks on genuine liberals as “reds” (and even though McCarthy made some charges that were accurate), the anti anti-communists came to argue that anyone accused by McCarthy or Richard Nixon or J. Edgar Hoover should be assumed to be entirely innocent. People like Hiss (a former State Department official who was accused of spying) cleverly hid their true espionage work by gaining sympathy as just another victim of a smear attack.

But now, with Sobell’s confession of guilt, that worldview has been demolished.

In the 1990s, when it was more than clear that the Rosenbergs had been real Soviet spies -- not simply a pair of idealistic left-wingers working innocently for peace with the Russians -- one of the Rosenberg’s sons, Michael, expressed the view that the reason his parents stayed firm and did not cooperate with the government was because they wanted to keep the government from creating “a massive spy show trial,” thereby earning “the thanks of generations of resisters to government repression.”

Today, he and his brother Robert run a fund giving grants to the children of those they deem “political prisoners,” such as convicted cop killer Mumia Abu-Jamal. Ironically, if there was any government that staged show trials for political ends, it was the government for which the Rosenbergs gave up their lives, that of the former Soviet Union.

This week, the Meeropols made it clear to the New York Times that they still believe the information their father passed to the Russians was not terribly significant, that the judge and the prosecutors in their parents’ case were guilty of misconduct, and that neither Julius nor Ethel should have been given the death penalty for their crimes.

On the subject of their mother, the Meeropols have a point. In another development last week, a federal court judge in New York released previously sealed grand jury testimony of key witnesses in the case, including that of Ruth Greenglass, Julius’ sister-in-law. It turns out that a key part of her testimony for the prosecution -- that Ethel had typed up notes for her husband to hand to the Soviets -- was most likely concocted.

That doesn’t mean that Ethel was innocent -- indeed, the preponderance of the evidence suggests she was not. But what is clear is that in seeking to get the defendants to confess to Soviet espionage, the prosecutors overstepped bounds and enhanced testimony to guarantee a conviction. Americans should have no problem acknowledging when such judicial transgressions take place, and in concluding that the execution of Ethel was a miscarriage of justice.

Nevertheless, after Sobell’s confession of guilt, all other conspiracy theories about the Rosenberg case should come to an end. A pillar of the left-wing culture of grievance has been finally shattered. The Rosenbergs were actual and dangerous Soviet spies. It is time the ranks of the left acknowledge that the United States had (and has) real enemies and that finding and prosecuting them is not evidence of repression.

Ronald Radosh, an emeritus professor of history at City University of New York and an adjunct senior fellow at the Hudson Institute, is the coauthor of “The Rosenberg File.”