Is the world becoming immune from America? Two dozen experts share their thoughts on a question with serious implications for the future of globalization.

Recently, The Economist magazine editorialized that any further U.S. economic slowdown in 2007 is unlikely to impede the growth of the rest of the world. In a world where America has been the consumer of last resort, "buoyant Asian demand should help keep Europe afloat despite a U.S. slowdown," the editorialists opined. European Central Bank President Jean Claude Trichet recently offered a similar assessment: "A 1.0 percent slowing in the United States" would subtract only "0.2 percent from growth in the Euro area, taking into account the echo effect from the rest of the world."

The counter argument is that because the Asian economies and the larger economies of the eurozone have become so export-dependent (while facing serious demographic problems in the years ahead), it is unlikely that a strong burst of consumption will rise up to take the American consumer's place. Some analysts add that the argument really centers on the effect on the world economy if U.S. growth drops below 2.0 percent. In other words, for every 1.0 percent U.S. growth declines below the 2.0 percent threshold, the Euro zone and Japan will decline 1.5 percent, with China and the other Asian economies declining perhaps a full 2.0 percent.

Historically, U.S. slowdowns and recessions have led to global slowdowns and recessions. Is that still true today?

Those who believe the world is becoming immune are kidding themselves.

KENNETH ROGOFF

Professor of Economics, Harvard University, and former Chief Economist, International Monetary Fund

The share of the United States in global output has indeed fallen over the past decades; it is now 20 percent, down from 25 percent. However, the reduced importance of the U.S. economy for world growth is partly an illusion, because the volatility of U.S. output growth has also dropped from what it was in the 1970s and 1980s. The fact that the United States has not been causing global business cycles as much as it used to does not imply that it no longer has the economic heft to do so.

That said, the United States' historical role in causing global business cycles is often exaggerated. The correlation between U.S. and other G7 country business cycles has historically been around 50 percent. However, a large part of this correlation owes to common shocks (oil, technology, housing), rather than to direct trade and financial linkages. That fact that U.S. income shocks seem to be such reliable harbingers of foreign shocks is partly because U.S. data is better and more reliable. It also tends to come in first. So no, Europeans (and Asians) who think that they don't need to worry if the U.S. economy tanks are kidding themselves.

The key point: America's economic influence reflects its dynamism and ideas, not its market share.

JAMES E. GLASSMAN

Managing Director and Senior Economist, JPMorgan Chase

The global economy has been hibernating for almost a decade. Asia's financial crises in the late 1990s left a deep scar across the region. Japan has been struggling with deflation. And Europe's growth has been frustratingly slow. All that seems to be changing and the global economy now is growing at its fastest pace in a long time. Does that now mean that America's economic influence will be on a slow decline?

It is true that the U.S. economy, with 5 percent of the world's population, has accounted for almost one-fifth of global economic growth since the late 1990s until recently. Global economic prospects are brightening as the industrial economies accelerate. Developing countries are emerging from the economic Dark Ages. If these promising trends continue, the U.S. economy will account for a smaller share of global economic activity.

But America's economic influence reflects its dynamism and ideas, not its market share. Indeed, U.S. exports will stand a much better chance when others achieve their full economic potential. Economic progress is not a zero-sum game, but instead enables the entire sum to grow, with benefits for everyone.

America's economy remains a global power house and its economic influence is still on the rise. America's current partnership with East Asia and India will do for 50 percent of the world's population what the Bretton Woods system did for 10 percent of the world's population from 1947-73. The linkup to the U.S. economy that helped to revive Europe and Japan after World War II certainly didn't drain energy from the U.S. economy. The resulting U.S. trade deficit was just another footnote. The emergence of a new Asian economy stands to strengthen America's standing in the global economy.

America's dominance in the global economy isn't about its physical infrastructure. Rather, its competitive market economy, intolerance of corporate governance flaws, risk-taking culture, and dynamic capital markets all reward entrepreneurs for transforming ideas into useful goods and services. Its dominance comes from the flexibility of its businesses to reinvent themselves amid sweeping global changes.

Predictions of the waning dominance of the American economy often fall out from a confusion about the forces driving the outsized U.S. international trade balance. Pessimists warn that destabilizing "global imbalances" are occurring because America is living beyond its means. It finances its "addiction" to consumption, the story goes, by borrowing from foreigners, including poor nations. After all, U.S. household saving is negative and the fiscal budget is in deficit. They believe that at some point America will be forced to abandon this reckless course and when that happens, its dominance will fade.

This vision is deeply flawed. In fact, the U.S. trade deficit has nothing to do with the United States. If U.S. over-consumption were the cause of global imbalances, the U.S. economy would be overheated. This is certainly not the case. For five years the economy has been recovering from a recession, even as the trade deficit widened. Indeed, as the trade deficit was deteriorating, U.S. policies were appropriately focused on economic revival. Benign inflation and labor's extremely low share of income relative to GDP are proof that the United States remains on a sustainable path. If U.S. consumers had not responded to rising net worth by saving less, or if U.S. fiscal policy had been less stimulative, the Federal Reserve would have needed to hold interest rates down for considerably longer than it did in order to revive the U.S. economy.

In fact, the U.S. trade deficit is the result of slow-growing industrial countries and rapid development in emerging economies. It reflects the profoundly favorable and stabilizing developments that are doing more to cure poverty than any other effort in memory. New consumers in most developing economies are too poor to reciprocate by purchasing goods and services made abroad. So, obviously rapid growth of developing nations is not benefiting U.S. exports just yet. This will change, however, as living standards rise across Asia.

From this perspective, the U.S. trade deficit is a positive force, a measure of the dominant role of the U.S. economy and its consumers in the unprecedented pace of globalization under way.

For those who fear the United States no longer makes anything the world wants and is slowly losing its global dominance, the truth is that the United States exports the most valuable commodity known. It exports hope and the promise of an idea that free markets are the most effective way to improve the living standard of the world's population. Asia's embrace of free market economics sends a powerful message that economies that embrace market principles will be tomorrow's economic powerhouses.

America is still relevant.

3. FRED BERGSTEN

Director, Peterson Institute for International Economics

A country or region must fulfill three characteristics to have an important impact on the global economy. It must be large. It must be dynamic, enjoying reasonably rapid growth. It must be relatively open to the rest of the world, with sufficiently deep international integration to produce important external repercussions from its own activity.

Only three components of the word economy now meet these three criteria: the United States, the European Union, and China. Japan, though the second largest national economy, never became sufficiently open to have a major global impact even during its decades of very rapid growth. Korea is neither large enough nor open enough. India is very large and growing very rapidly but is still too closed to outside influences to have much worldwide impact.

Significant changes in economic activity in any of the three current economic superpowers will have important effects on the global economy as a whole. The United States is no longer alone in levying such effects, however, as it was in the early postwar period. Nor is it joined in that impact only by the unified European economy, as it was until the last few years. China has now joined this league and will have an increasingly important international impact as long as its rapid growth, and open trade and investment policies, continue.

If the United States slows seriously, Asia and Europe should brace themselves for a sudden halt to growth.

TADASHI NAKAMAE

President, Nakamae International Economic Research

The world should brace itself for a sudden halt to growth if the United States enters a recession. Contraction in the consumption-driven U.S. economy will trigger a drop in the country's appetite for imports, thereby reducing its huge current account deficit. The narrowing deficit will, in turn, be a drain on global liquidity.

The biggest problem facing the world economy--Asia, in particular--is excess supply capacity. The investment boom of recent years has led to a large over-supply of many tradable goods (steel, cars, electronics, and so forth)--most dramatically in China. Any decrease in demand will further raise surplus capacity. Worldwide capital expenditure--especially...