Pete Seeger, America’s best-known and most influential folksinger, wrote me a letter a few days ago. I did not expect to hear from him. Last June, I wrote in these pages about the new documentary on his life. The article ran under the headline “Time for Pete Seeger To Repent.”

My complaint was that the film, good as it is, did not give a completely honest account of Mr. Seeger’s politics. The filmmaker, Jim Brown, interviewed me on camera, but he did not include any of my critical remarks in the final version. In my interview, I pointed out that Mr. Seeger had been a lifelong follower of the Communist Party, changing his songs and his positions to be in accord with the ever-changing party line. He attacked the blacklist of the 1950s, which kept him off the air, but never seems to have said anything about Stalin’s death list. As Martin Edlund has written in The New York Sun, Mr. Seeger has always been inseparable from his social mission. Much of it deserves praise – he was at the forefront of the struggle for civil rights – but much of it must be condemned and not hidden from sight.

In particular, I said that Mr. Seeger had supported Stalin’s tyranny for so many years yet had never written a song about the Gulag. Yet some acknowledgment of his former support would have been appropriate, especially considering the songs he has sung about the Nazi death camps, which he often introduces by saying, “We must never forget.”

So I felt some trepidation when I got Mr. Seeger’s letter. Surely he was angry, or at the least peeved, by my article. I had been a banjo student of his in the 1950s and regarded Mr. Seeger as my childhood hero and mentor. But for decades since then, I have been publicly identified as an opponent of much of what he has believed — that the Rosenbergs were innocent, for example, or that Fidel Castro was a friend of the poor.

I almost fell off the chair when I read Mr. Seeger’s words: “I think you’re right – I should have asked to see the gulags when I was in [the] USSR.” For years, Mr. Seeger continued, he had been trying to get people to realize that any social change had to be nonviolent, in the fashion sought by Martin Luther King Jr. Mr. Seeger had hoped, he explained, that both Khrushchev and later Gorbachev would “open things up.” He acknowledged that he underestimated, and perhaps still does, “how the majority of the human race has faith in violence.”

More importantly, Mr. Seeger attached the words and music for a song he had written, “thinking what Woody [Guthrie] might have written had he been around” to see the death of his old Communist dream. Called “The Big Joe Blues,” it’s a yodeling Jimmie Rodgers-type song, he said. It not only makes the point that Joe Stalin was far more dangerous and a threat than Joe McCarthy – a man Mr. Seeger and the old left view as the quintessential American demagogue – but emphasizes the horrors that Stalin brought.

“I’m singing about old Joe, cruel Joe,” the lyrics read. “He ruled with an iron hand / He put an end to the dreams / Of so many in every land / He had a chance to make / A brand new start for the human race / Instead he set it back / Right in the same nasty place / I got the Big Joe Blues / (Keep your mouth shut or you will die fast) / I got the Big Joe Blues / (Do this job, no questions asked) / I got the Big Joe Blues.”

Mr. Seeger continued in his letter to me: “the basic mistake was Lenin’s faith in [Party] DISCIPLINE!” He often tells his left-wing audiences, he said, to read Rosa Luxemburg’s famous letter to Lenin about the necessity of freedom of speech. And despite all of my criticisms of Mr. Seeger over the years, he ended warmly, saying: “You stay well. Keep on.”

I was deeply moved that Mr. Seeger, now in his late 80s, had decided to acknowledge what had been his major blind spot – opposing social injustice in America while supporting the most tyrannical of regimes abroad. Mr. Seeger rarely performs anymore. But if he does, and if he sings this song, I suspect that few in the audience would have any idea of what it is about. And I doubt that any other singer today would cover it. Only an audience composed entirely of the now-aging old left veterans would understand it instantly. Undoubtedly, many of them would be shocked.

I phoned Mr. Seeger at his home in Beacon, NY, and thanked him for his letter and its warm and supportive tone. We spent some time reminiscing about the old days and people we knew and things we had experienced together. Turning to a discussion of the community he lives in, Mr. Seeger told me he’s a friend of the Republican mayor of his town, who sponsors community events and welcomes him as a participant. Mr. Seeger, it is clear, believes in bringing people together for good works, and in reconciliation.

Mr. Seeger is still a man of the political left, and I’m certain we disagree about much. But I never thought I would hear him acknowledge the realities of Stalinism. I honor and admire him for doing so now.