Americans have time on their minds and none on their hands. This December the year's busiest holiday season collides with the ending of the present decade, century and millennium. The world encounters Christmas, Hanukkah, Kwanzaa, Ramadan and the rolling over of Father Time's triple zeroes across 31 momentous days.

The coming together of energetic consumerism and vast historical perspectives is not without justice. America's economic success over the past decade and the end of the Cold War are the two biggest stories of our day. They are linked not only in time but in substance.

The borrowing, buying and selling that reaches a crescendo in December is of course essential to the American economic success story. But consumerism also played an important inspirational part in the demise of communism and the Soviet empire. The holiday season is a perfect moment to reflect on both.

The Berlin Wall fell 10 years ago because it blocked access to freedom, ideas, cultural diversity -- and consumer goods and services. Catholic priests in Warsaw and intellectuals in Dresden today bemoan the gaudy, materialistic and amoral societies they see emerging from the ruins of drab dictatorship. But such regret over the choices their fellow citizens are now free to make usually neglects the noble role that the hunger for Western standards helped play in toppling the Iron Curtain.

Think too how American consumers have changed the face of the world over the past 10 years: They bought China out of dire poverty, provided profits for pension funds to pump into European companies and Chilean factories alike and helped finance the spread of the Internet. The return of their European and Japanese cousins to the stores and markets in recent months fuels hope for strong global recovery in 2000.

The global economy should grow by 3.5 percent next year, the Paris-based Organization for Economic Cooperation and Development (OECD) reported in mid-November. The OECD moved its 2000 projection for Japan from zero to 1.4 percent growth. The 11 European countries that have adopted the euro as their currency are expected to have 2.8 percent growth, close to the projected U.S. rate of 3.1 percent.

But Americans have not only been consuming. They have been investing in epic proportions. Today 76 million Americans, who belong to 43 percent of all U.S. households, own stock or stock mutual funds, Richard Nadler writes in a recent study for the Cato Institute. They represent "the most significant demographic shift of this century" because they are "history's first mass class of worker capitalists."

Nadler's study concentrates on the economic consequences of this explosive growth in shareholding. But the political effect is, I believe, equally important. As workers buy stock, they tend to move to a blurry political center away from ideological extremes. They support balanced budgets and lower taxes. They back Bill Clinton's new Democrats or George W. Bush's compassionate conservatism in the United States, Tony Blair's new labor in Britain or Lionel Jospin's pragmatic socialism in France.

Investment banker Felix G. Rohatyn, currently U.S. ambassador to France, has developed an analysis of this "popular capitalism" in recent speeches. He urges Europeans to comprehend and emulate the American practice of employees taking equity ownership in their, and other, enterprises.

"The American and European economies are roughly similar in size," Rohatyn says, "the same population, the same GNP, a similar standard of living." But the amount of capital Americans have invested in stock and bond markets "is almost three times the market capitalization of the European stock markets combined. This is the result in part of the compound effect of heavy investment in high-growth industries for the last 50 years" in the United States.

In this decade the United States has gone from running a $300 billion-a-year deficit to a $123 billion surplus in fiscal year 1999. This represents "a shift of more than $400 billion per annum from expenses to investment," Rohatyn notes. This accomplishment comes 25 years after American society was portrayed as being in decline, with Japan and Germany painted as the economic models of the future.

History's inexorable pendulum swung back the other way. Americans can take great pride in that swing. But the unforeseen economic road the United States traveled in the second millennium's final quarter-century also warns against indulging national hubris and selfishness. Assumptions that tomorrow's harvest will be as abundant as today's are certain to be as flawed as were the dire predictions of yesterday.