The death of Aleksandr Solzhenitsyn, coming as it does amid a great new struggle between the free and unfree worlds, brings to mind a story the editor of the Sun likes to tell his colleagues. It was during the years of Solzhenitsyn’s exile in America, when he turned his Vermont estate into a latter-day version of Tolstoy’s famous retreat, Yasnaya Polyana. The editor, who was then working at the Wall Street Journal, was about to make, with a number of the Journal’s other editors, a trip to the Soviet Union. So he sent Solzhenitsyn an invitation to join the editors for dinner. The writer, who lived a reclusive life, sent a short but gracious note to say that he was unable to get to New York but that his advice to the editors was: “Remember, there is such a thing as good and evil.”

It was his steadfast belief in good and evil, and his conviction that he was destined to play a part in the struggle between them, that made Solzhenitsyn’s one of the emblematic lives of the 20th century. With his passing, we have lost one of our last links to the era of Soviet tyranny and the struggle to defeat it. Solzhenitsyn did not play the same kind of political role in that struggle as some of the other giants of the 20th century with whom his name should be remembered — Pope John Paul II, Ronald Reagan, Margaret Thatcher. But as a writer and witness, his contribution was no less crucial.

For the first step in resisting evil is to identify it as such, and once Solzhenitsyn had written, no one could any longer doubt that the evil of Stalinism was comparable to the evil of Nazism. What Primo Levi did for the Nazi death camps in “Survival at Auschwitz,” Solzhenitsyn did for the Soviet prison camps in “One Day in the Life of Ivan Denisovich,” his first novel, and the one that made him famous around the world. That book, published in 1962 during Khruschev’s brief thaw, chronicled what life was like in the Gulag: the torture, the starvation, the freezing, the killing labor, the unjust punishments, the desperate struggle to live another day.

“How can you expect a man who’s warm to understand a man who’s cold?” Ivan Denisovich asks. Even as late as 1962, the warm readers of the West did not all know — or, in all too many cases, want to know — just how cold it was in the USSR. To make them feel, it took a great writer who was also a great witness. In order to write his searing books — after “Ivan Denisovich” came “The First Circle,” “Cancer Ward,” and supremely, “The Gulag Archipelago,” which made the word “Gulag” part of the English language — Solzhenitsyn first had to survive the experiences they chronicle.

In 1945, after serving in the Red Army as an artilleryman for three years, he was thrown into prison as a spy and traitor. The basis for his conviction was a disrespectful phrase about Stalin, used in a letter home. Of course, no real crime was needed: Stalin sent tens of millions of innocent men and women to prison, and Solzhenitsyn’s fate was to serve as their historian. In his biography of the writer, Michael Scammell quotes some of the letters he received from his fellow zeks about his first book: “My face was smothered in tears … all this was mine, intimately mine, mine for every day of the fifteen years I spent in the camps”; “As I read it, at last I felt myself to be an equal citizen to the rest”; “I would give you anything, anything.”

* * *

What link can we find to a figure like Solzhenitsyn today? The left compares America’s holding of enemy detainees at Guantanamo and elsewhere to the Gulag. But as it happens, if it is happenstance, one of our candidates for president, Senator McCain, had himself been a prisoner of Communism, and will no doubt not fall for such a comparison. He was among those inspired by Solzhenitsyn’s work. He wrote about it, with Mark Salter, in a book called “Hard Call: The Art of Great Decisions,” which we excerpt nearby. Mr. McCain reminds that the Russian wrote not only “diligently, comprehensively, profoundly” but also in secret and that his decision to publish carried enormous risks. Mr. McCain clearly comprehends the impact of Solzhenitsyn’s writings, of the power of words, of art, and of truth. It is something that went way beyond Solzhenitsyn’s Nobel Prize, and it is something for our leaders to know deep down, now that we are again in a time to remember that there is such a thing as good and evil.