Few Americans recognized the name Morton Sobell when his recent death at age 101 was disclosed last week.

But for much of the Left, it was long an article of faith that Sobell and his co-defendants, Julius and Ethel Rosenberg, had been framed for their radical politics and were never Soviet spies, as the government charged. In these circles, the Rosenbergs’ execution in 1953 counts as a great outrage.

But a decade ago, Sobell, who served 18 years of a 30-year prison sentence, stunned his former comrades by confessing all.

Yes, he admitted, he and the Rosenbergs were dedicated communists who’d stolen US military secrets and passed them to Moscow, though he “never thought of it” as espionage.

True, he tried to dismiss the seriousness of their crimes by insisting they only supplied info on “defensive” weapons, like artillery and radar, that couldn’t be used to “attack our country.”

But history says otherwise. While the Rosenberg ring did not, as prosecutors charged, reveal the “secret” of the atomic bomb, it did provide information on the bomb project.

And, as historian Steve Usdin has noted, the ring turned over detailed information on “a wide range of technologies that hastened the Red Army’s march to Berlin” (allowing Moscow to dominate Eastern Europe for nearly five decades), “jump-started its postwar development of nuclear weapons and delivery systems and later helped Communist troops in North Korea fight the American Army to a standstill.”

In other words, guilty as charged. Whatever the reason for his belated confession (and he was still as radical as ever), the verdict of history is clear: Morton Sobell and the Rosenbergs were no martyrs and the courts got it exactly right.