During the past year, emerging Asian economies have shown two tremendous sensitivities.

One, their export dependence has made them highly vulnerable to the global economic softness and made for grim Asian economic news late last year and earlier this year.

And two, their high responsiveness to any policy stimulus has more recently created something of an Asian economic resurgence.

In fact, that second sensitivity—the response to stimulus—has occurred even as exports to the West's still-soft economies languish. So, as the American and European economies recover and improve export prospects from those emerging Asian economies, the recent positive momentum will continue to build.

From late 2008 until this past spring, the economic picture in emerging Asia looked ugly. Even though China, India, Hong Kong, Taiwan, South Korea, Malaysia, and other nations in the group had little direct exposure to the subprime and other financial difficulties that beset America and Europe, their export dependence weighed them down as the West's recession choked world trade. This was clearly evident from the plunge in the Baltic dry-freight index, which measures changes in the cost to transport raw materials. The index went from 12,000 in early 2008 to a mere 500 earlier this year. And these Asian economies had an even more exaggerated response because they are so export dependant.

Growth in the two giants, China and India, continued throughout this time but it slowed dramatically. By spring 2009, China was widely described as growing in real terms at a 6.5% annually, enviable by the standards of most countries but only half its growth rate in 2007, and two-thirds the rate it recorded for 2008.

India saw its pace of real growth shrink to an annual rate of 4.5% earlier this year, compared to approximately 7% to 8% in 2007 and 2008. The smaller economies of the region, which are even more tied to exports than these heavyweights, suffered outright declines. By spring 2009, Hong Kong was expected to suffer a 6.0% decline in its real gross domestic product for the year; Taiwan, a 7.5% decline, Singapore, a 10% decline; Malaysia, 3.5%; South Korea, 4%; and Thailand, 3%.

But by summer, things had improved. July and August commentary from the International Monetary Fund, the World Bank, and a raft of private forecasters all acknowledged strong signs of recovery in every one of these economies.

Hong Kong benefited from a surge in exports to mainland China, by 11% in just the last quarter. Prospects for the rest of the year show enough growth to improve last spring's consensus forecast of a 6% overall decline for the year to a 4% decline. In a similar way, South Korea has raised its real GDP expectation for 2009 by 2.5 percentage points and now expects a full year drop of only 1.5% Others of these economies show the same pattern.

China had accelerated enough so that its 2009 target growth of 8% started to look probable and India's growth accelerated enough to generate a consensus forecast of 6% real growth for the year.

And India probably would have done even better were it not for the decline in monsoon rains that set back that country's important agricultural sector.

The key to this recovery comes from the aggressive stimulus programs that many of these countries put in place last year or early this year, as the reality of their former economic shortfalls became apparent. South Korea, India, Malaysia, and especially China all eased their monetary policy levers and engaged in fiscal stimulus to the extent that they could. China, of course, made the biggest splash with its 4 trillion yuan ($580 billion) infrastructure program and with interest rate cuts of over 200 basis points as well as a 200 basis point reduction in bank capital requirements. India, constrained by an already difficult budget situation and a sovereign rating downgrade to triple-B, nonetheless initiated stimulus spending so that nation's budget deficit now approaches 10% of GDP. South Korea, Malaysia, and other nations in this group made similar efforts.

Certainly by comparison to the situation in the United States, all these economies have responded quickly and dramatically to their respective stimulus programs, even though their exports to markets outside the region remain down about 20% from their peaks.

The main locomotive in this remarkable response, not surprisingly, is China. To be sure, its infrastructure program is massive. It alone amounts to about 14% of that nation's GDP. (By comparison, President Barack Obama's $750 billion fiscal stimulus program amounted to a bit over 5% of the GDP of the United States.) But even apart from size, China's policy efforts and those of others in Asia have had a more powerful effect on these economies than America's program has here for two important reasons.