Forty years ago this month, my life took a new path. Forty years later, I’m still on that path.

The year was 1974. U.S. President Richard Nixon and Soviet Chairman Leonid Brezhnev had introduced the word “détente” into the Cold War vocabulary. One of the outcomes was a series of annual Soviet-American exchange programs designed, at least in theory, to widen contacts between the two countries. One such initiative brought six teachers from the USSR to the U.S. for several months to teach Russian language and culture in American schools, and vice versa.

I was one of the six Americans selected to live and work in the Soviet Union in the fall of 1974. I was 25 years old.

I went with a sense of youthful idealism, believing that such person-to-person contact could help ease tensions between nations, even as I had some grasp of the totalitarian nature of the Soviet regime.

My mother and her family had fled Soviet communism decades earlier and, shall we say, had no nostalgia for it. I knew that Moscow had crushed the Prague Spring in 1968 and the Hungarian uprising 12 years earlier. I followed the repressive campaigns against Soviet dissidents, and I was aware that Jews suffered from state-initiated persecution.

Still, I departed New York’s Kennedy Airport with hope and enthusiasm.

It didn’t take me long, though, to figure out that things were far worse than I ever could have imagined.

In those days, the Soviets wanted some Western visitors, but only those whose visits they could choreograph. Officials believed that days filled with organized trips to sites sure to impress — from the ballet to the metro system — and encounters with regime mouthpieces could create new Western spokespersons for such notions as “The USSR is far better than I ever imagined,” “The people seem happy,” “I didn’t see any signs of repression,” and “You know, every country has its challenges, be it the USSR or the U.S., but we’re all basically alike.”

But the country didn’t really know what to do with the concept of a Russian-speaking teacher who was actually living there, going to work six days a week, and not assigned to any tourist or business group and its official minders.

And so the painstakingly-constructed Potemkin Village of Soviet life quickly crumbled, to be replaced for me by growing awareness, from day to day, of a vast system built on tight control, fear and intimidation, economic inefficiency, and widespread social pathologies.

Russian President Vladimir Putin may think that the collapse of the Soviet Union was “the greatest geopolitical catastrophe of the 20th century,” but I beg to differ. The unprecedented model of state repression and central control of the economy was not sustainable, nor should its disappearance be rued for a single moment.

But what really hit me was the treatment of the Jewish population.

Not quite 30 years after World War II, in which the Soviets had fought tenaciously — after the German invasion in June 1941 shattered the Ribentropp-Molotov agreement — to defeat Hitler (and liberated Auschwitz in the process), Moscow was carrying out a campaign of cultural genocide against millions of Jews.

It was certainly more subtle than the Nazi effort, and didn’t entail mass deportations and death camps, but it did seek to stamp out all vestiges of Jewish life, dole out a painfully high price to those who resisted, and assail Israel and Zionism from morning till night.

In my months living and teaching, first, in Moscow, then in Leningrad (aka St. Petersburg), I saw all this from the ground up.

But then I also witnessed something else that touched me far more deeply than I could ever have imagined — and that ultimately altered the course of my life.

I saw some Jews fighting back. They were unwilling to be cowed or bullied, even if the price for their defiance was daily harassment, loss of jobs, difficulties for their spouses and children, or, most ominously, imprisonment in the Gulag.

All that I had taken for granted in my life as an American Jew was the focus of these modern-day heroes.

Whether it was the right to worship freely or openly wear a Star of David, to study Hebrew or read Leon Uris’s Exodus, to learn about Israel or pay homage to the memory of Holocaust victims, or to celebrate holidays or organize a Bar or Bat Mitzvah, none of this was permitted in the Soviet Union. To the contrary, each entailed significant risks.

For these heroes, their lifeline was the West, and, above all, the Jewish world. The fate of those who challenged Kremlin authority had not been a pretty one since 1917. Why should Jews in 1974 experience anything different? The answer, I came to understand, lay, first and foremost, in Jewish solidarity. It meant ensuring that Soviet Jews never felt alone. No Iron Curtain could keep Jews apart, allowing the Soviets to do what they wished with impunity.

And no less importantly, it meant mobilizing public opinion, especially in the U.S., and urging the American government to convey the stark message that “détente” without steps to improve the lives of Jews, and allow emigration for those who wished to resettle in Israel and elsewhere, was an empty shell.

By the time I was detained by Soviet authorities on a frigid December day, shortly after leaving the one synagogue remaining in Moscow — which existed mostly as a showpiece for Westerners — and put on a plane to Helsinki, I understood that my life had changed irreversibly.

I had met many Soviet Jews, visited some homes, befriended several “refuseniks” who were living in limbo between their desire to leave and their inability to do so, and heard — in hushed tones, of course — individual stories of discrimination and persecution, coupled with dreams of new lives abroad as Jews.

Rather than wonder what I might have done during the Holocaust were I alive, I was confronted with the great challenge of my era — to be that lifeline for Soviet Jews, prevent cultural genocide, and show that we could stand strong, even against the most powerful totalitarian regime on earth.

And so within three months of my unplanned arrival in the Finnish capital, I was working in Rome, where Soviet Jews lucky enough to get out were being processed for onward travel and resettlement. Then came Vienna, the first arrival point in the West for arriving Soviet refugees. And then came AJC from 1979 onward. There were no more thoughts of the State Department or UN as a career path.

I’ve learned a lot in these past four decades, since seeing Moscow for the very first time.

Above all, I grasped two essential lessons.

It’s totally up to each of us. If not us, who?

And the seemingly impossible can be achieved. Not easily by any stretch, but the story of Soviet Jewry is ultimately one of redemption and renewal.

Now fast forward to 2014.

Jews face new threats and dangers, from efforts to isolate and demonize Israel to growing questions about the very future of some Jewish communities in Europe.

Isn’t it time for each of us to ask how we can help — and to remind ourselves that, however immense the challenges, history has shown they can be surmounted?