Nearly everyone is familiar today with President Ronald Reagan's demand, delivered in Berlin in June 1987, that Soviet leader Mikhail Gorbachev "tear down this wall." They may not be aware of his comments during a visit to West Berlin five years earlier.

"At this very moment, the forces of the Soviet Union and the Warsaw Pact are poised only a few miles from here," Reagan said in June 1982. "They aren't there to protect the people of Eastern Europe. The Iron Curtain wasn't woven to keep people out; it's there to keep people in. The most obvious symbol of this is the Berlin Wall. And, you know, if I had a chance, I'd like to ask the Soviet leaders one question ... Why is that wall there?"

He then answered his own question: "They know that freedom is catching, and they don't dare leave their people to have a taste of it."

These words were prescient, and not just in the general sense. The fall of the Berlin Wall, 30 years ago tonight, took place because too many East Germans got a small taste of freedom in their mouths. This was fatal to the survival of state socialism.

Of course, the communists had an official explanation for why the wall was there — they referred to it as the "antifaschistischer Schutzwall," or "anti-fascist protective barrier." It is both telling and disturbing that the term "anti-fascist," used for so many decades by communists to justify violence and political repression, is coming back into use today. Of course, this explanation did not pass the laugh test even when it was first used.

In April 1989, the communist government of Hungary quietly removed the electric fence that had long separated that country from Austria, its free and democratic neighbor. Word quickly spread to East Germany, arguably the most repressive communist state in Europe, but also the wealthiest, that people could escape by simply traveling to Hungary through neighboring Czechoslovakia.

The East German regime tried to stem the consequent tide of emigration by closing the southern border. But by fall, the ailing and fiscally failing regime was losing its grip. Erich Honecker, general secretary of the East German Communist Party, begged the Soviet leadership to send in tanks and quell growing anti-communist sentiment. Gorbachev, to his great credit, refused, unwilling to repeat the bloodshed of communist crackdowns that had occurred decades earlier in Hungary and Czechoslovakia.

The East German politburo finally ousted Honecker in mid-October and, in a desperate bid to retain power over a restless population, set out to soften its image. In early November, the communist leaders drafted a new travel law that would ease the onerous requirements on East Germans seeking permission to travel abroad. People would be able to leave in almost all cases, and without even having to travel through third countries.

The new rules were not supposed to be announced until Nov. 10, but a confused Communist Party functionary accidentally let the cat out of the bag during a Nov. 9 press conference. His announcement was broadcast on West German television in the 7 o'clock hour, and by 10 p.m., thousands of East Berliners had flooded their city's six border checkpoints. The guards finally relented and began opening the gates. By midnight local time, the process of tearing down the Berlin Wall had begun.

Although the German Democratic Republic lived on for almost another year, it really ended the moment people got the taste of freedom in their mouths. The bureaucrats and officials, who thought their socialist philosophy would bring about the end of history, were themselves cast upon its ash heap.

Thirty years later, it is hard to believe that the Berlin Wall has already been gone longer than it stood. But its remaining sections, shipped to locations throughout the world, stand as a reminder of what Reagan often said: freedom is never more than one generation away from extinction.

All it will take for fascist or socialist tyranny to return is for one generation to forget the lessons of the past, or to decide that the burdens and risks and responsibilities of freedom are too great to bear, and that bureaucrats in some distant capital should be given the power to direct our lives. May that never happen in the lifetime of anyone who reads this.