Ronald Reagan's death has a special significance for those of us who were the children of the "Reagan revolution." In early 1987, I joined the Reagan White House as a senior domestic policy analyst. I was part of a generation of young conservatives drawn to Washington in the 1980s, inspired by Mr. Reagan and the idea of America that he espoused.
What we found new about Reagan was his bold and optimistic challenge to collectivism. Collectivism was the great idea of the 20th century, and opposition to it was the unifying element of Reagan's thought.
Soviet socialism, what Reagan called the "Evil Empire," was only the most grotesque example of collectivism taken to its extreme limit.
At home, Reagan was equally fierce in resisting the expansion of the welfare state. With typical aplomb, he announced that "government is not the solution, government is the problem."
I had come to Washington initially as a journalist, writing articles about the Reagan revolution. But by the time I joined the White House, I must confess that my enthusiasm about Reagan was waning. Reagan had been in office for six years, and little had changed. He spoke about cutting the size of government, but government was bigger than ever. The Soviet bear remained on the prowl, without suffering a single major defeat at Reagan's hands.
Moreover, Reagan seemed a poor administrator. The Iran-contra scandal had erupted in late 1986, and chaos abounded in the White House. No one appeared to be in charge.
The president struck me, and many of my colleagues, as somewhat detached from the everyday responsibilities of high office. Many of us continued to believe the things he said; we just didn't think he would do them. We were genuinely fond of Reagan, but we worried that he was not a very effective leader, certainly not the revolutionary he once seemed to be.
Now, with more than 15 years of hindsight, I realize how wrong I was. Reagan badly bungled the Iran affair, but his original motive in selling arms to Iran was to bring American hostages home, so people eventually forgave him, and Iran-contra quickly became a historical footnote.
While many people - both critics and supporters - were obsessed with minutiae, such as whether this Labor Department regulation should be continued, or whether that tax loophole should be closed, Reagan over his two terms somehow managed to keep focused on the big issues, and he brought about massive changes that came to full fruition only after he had left office.
I remember sitting in the Old Executive Office Building with other White House staffers in 1987 watching Reagan on television deliver his address in Berlin before the Brandenburg Gate: "Mr. Gorbachev, tear down this wall!"
And we cheered the old boy and marveled at his rhetoric - a bit hyperbolic, perhaps, but those were words that needed to be said.
Which of us knew then, though, that only two years later, the Berlin Wall would come crashing down? No one.
The event simply seemed too large, too momentous, to contemplate. So nobody expected it, and nobody predicted it. Except Reagan.
Early in his presidency Reagan repeatedly said that the death of Soviet communism was imminent. In 1981 he said at the University of Notre Dame, "The West will not contain Communism. It will transcend Communism. It will dismiss it as a bizarre chapter in human history whose last pages are even now being written."
At the time, there was virtual unanimity across the political spectrum that the Soviet empire was permanent. Reagan's top Soviet advisers were part of that consensus. Reagan was almost unique in the Western world in seeing the fragility at the heart of the Soviet system.
Not only was Reagan prophetic in forecasting the Soviet demise, he was prescient in the strategy he employed to hasten it.
In the first term, Reagan was tough in dealing with the Russians, while the liberals warned that he was leading the world closer to nuclear holocaust.
In the second term, Reagan was soft in dealing with the new Soviet leader, Gorbachev, while many conservatives worried that Reagan was being outmaneuvered. I confess to being one of those conservatives.
But with hindsight, we can now see that it was Reagan, and only Reagan, who was right all along. He shepherded the "Evil Empire" to its grave with almost uncanny prescience and statesmanship.
When has a great empire succumbed with so little loss of life?
The miracle of the cold war was that it was a war not made, but prevented. We owe Reagan a lot for that.
Margaret Thatcher said a few years ago that "Reagan won the cold war without firing a shot."
That comes close to defining his legacy.
But it's not quite enough.
Reagan's second major accomplishment is to bring about a major shift in American culture.
To understand this, it helps to go back a generation and recall President Kennedy's rallying cry to young people.
If you are idealistic, Kennedy said, if you care, you should join the Peace Corps, you should become a "public servant." And millions of Americans did.
Since the 1960s the "public servant" was seen as the height of American idealism. If you tried to make money in the private sector you were seen as selfish and greedy, but if you joined the government, you were seen as serving the common good.
Reagan challenged this view. For him, the "public servant" was nothing more than a "bureaucrat." Reagan contrasted the do-nothing bureaucrat with the entrepreneur. In his view the entrepreneur who uses creativity and imagination to produce things that didn't exist before, was the embodiment of American possibility.
We are now living in an entrepreneurial era. We are living in a country where virtually everyone now accepts that the market, not the government, will basically run the economy.
Even Bill Clinton admitted during the 1990s that "the era of Big Government is over."
Reagan, more than any single person, brought about this shift in the culture and in policy. His vision has decisively triumphed over Kennedy's. And the era of collectivism that began in 1932 with Franklin Roosevelt's New Deal came to an end in 1989 when the Berlin Wall fell.
Many historians who have opposed Reagan all his life cannot bring themselves to credit his accomplishments. But even many of us who supported Reagan and worked for him underestimated his effectiveness. We liked him as a person and felt he had the right ideas, but we didn't think he could do what he did.
Only in retrospect do we see how much he accomplished. And in time, most people will also see this.
History, I am convinced, will view Reagan as one of our greatest presidents. He won the cold war and launched the world into a new era.
The US now faces new challenges such as Islamic radicalism and fundamentalism.
But Reagan helped give America the military, economic, and moral strength to face these challenges. We owe him an immense debt, for which we should be grateful.
• Dinesh D'Souza is a scholar at the Hoover Institution at Stanford University. He is author of 'Ronald Reagan: How an Ordinary Man Became an Extraordinary Leader.'