Twenty years ago, my wife, Jan, and I were in what was then called West Berlin for a conference. One pleasant afternoon we walked along the Berlin Wall from the Brandenburg Gate to Checkpoint Charlie. During that time, there were significant rancorous anti-Communist demonstrations in East Germany, primarily in the southern part. A German friend, with typical Prussian hubris, dismissed them. "Nothing will come of this, these are just the ineffective rumblings of a bunch of Bavarians."

Three weeks later, the wall fell.

Like many of you, I remember when the wall was built. I remember President John F. Kennedy's speech. The wall coming down seemed impossible. The Cold War seemed to be a permanent condition. The Soviet empire and the West were deadlocked.

But not everyone believed that.

Next week, we will celebrate the fall of the wall, to the astonishment of the world.

How and why did it happen?

Though success has many fathers, three people deserve enormous credit: Ronald Reagan, Margaret Thatcher and Pope John Paul II. I do not mean to shortchange Mikhail Gorbachev. He played an important role, but mostly in reaction to the affirmative moves of the troika.

Reagan was ridiculed by the conventional-wisdom crowd for his quaint anti-communism. He embarrassed many, including some in his administration, with his talk of the evil empire. He was thought na?e in his persistence in seeking nuclear disarmament. He was considered rude and unsophisticated when negotiations with Gorbachev collapsed at the Reykjavik summit because of his refusal to abandon his Strategic Defense Initiative. Yet a year later, Reagan and Gorbachev signed the first nuclear-arms reduction of the Cold War.

Reagan's principal tactic to bring an end to the Cold War was to build up conventional weapons and deploy them in Europe. Possibly more significant, however, was the weapon of his rhetoric. (His famous Brandenburg Gate speech was given in June 1986, between the collapse of the Reykjavik Summit and the eventual signing of the nuclear-arms-reduction treaty in December 1987). "General Secretary Gorbachev, if you seek peace, if you seek prosperity for the Soviet Union and Eastern Europe, if you seek liberalization, come here to this gate. Mr. Gorbachev, open this gate. Mr. Gorbachev, tear down this wall!"

Thatcher was also indispensable in bringing down the wall. She was a natural and strong ally of Reagan in the quest to dismantle the Soviet empire.

John O'Sullivan, in an article in USA Today, wrote that Thatcher "was the most consistent, outspoken, determined and reliable friend to Reagan and the United States in this final climactic struggle with totalitarian communism."