On Thursday, a much-beloved, extremely influential, much-reviled American thinker died. He helped shape an ideological and political revolution here and overseas. Some call him a genius who told the truth, once and for all; just as many call him an architect of an era of selfishness and backwardness.

But then, that's what great thinkers and great thoughts do - provoke passion. Whether you liked him or not, when economist Milton Friedman died, America lost one of its most prominent, most effective thinkers about the wealth of nations. In economics, only a few other names - Smith, Marx, Keynes, Galbraith - rank with his.

No American economist had a more distinguished career. Friedman entered government work as a worker for New Deal programs. In 1946 he became a professor at the University of Chicago, where he taught for the next 30 years. In the 1950s, he helped build the Chicago School of Economics, which has produced eight Nobel Prize-winners.

In 1962, he published Capitalism and Freedom, his great statement of the belief that shrinking government's role in the free market would give people more freedom. The next year, he and Anna Schwartz published A Monetary History of the United States, which suggested that changes in the money supply could drive changes in the economy.

In 1976, he won the Nobel Prize for Economics. Four years later, his TV show Free to Choose ran on PBS. The resulting book, cowritten with his wife, Rose, may as well have been a salvo for the Reagan Revolution. Friedman, who thought of himself as a libertarian rather than a doctrinaire conservative, joined President Reagan's Economic Policy Advisory Board in 1981. He received the 1988 National Medal of Science and the 1988 Presidential Medal of Freedom.

Was he right? The jury is out and probably always will be. His most famous single dictum was that private individuals will put their money to better use than government ever can for them. But do Americans merit such trust? U.S. consumers have a lousy rate of savings; the way they use their money, all too often, is to spend it. Individually and as a country, we're addicted to red ink. And - granting the controversy over its true extent - poverty is still poverty, with no solution, public or private, in sight. Some economists and politicians are starting to see the United States as - gasp! - an undertaxed nation. And many, many are the services the private sector either can't or won't provide.

Yet Friedman's legacy is indeed vast. The U.S. government is much smaller than it once was, federal taxes much lower. Much of what government once did now lies in private hands (sometimes - think "Halliburton" - less than happily). We have an all-volunteer Army. Our reformed welfare system lays greater stress on work. Around the country, school districts are instituting vouchers, charter schools, and other ways of injecting competition into the previous government monopoly on public education.

In the private sector, employers are moving away from pensions, obliging individuals to provide for more and more of their own futures. And we have become more of an entrepreneurial culture, more conscious of our power to invest and share in the larger economy.

Much of that is good; much is troubled. But what a vast, swift revolution (26 years). It's a reality and will remain so for generations.

The most regrettable thing about Friedman's ideas is how others used them. Seized upon by trenchantly partisan advocates, they quickly became, not an economics, but a theology. In the sour echo-chamber of American politics, you either were a true believer or an infidel.

For his part, Friedman wanted not a religion but a more free republic. His ideas and efforts toward that end have helped make this country what it is today. Some will say for better; others will say for worse.