"Every system needs a stabilizer -- one stabilizer," concluded the great MIT political economist Charles Kindleberger in his classic study of the Great Depression of the 1930s.

The problem before World War II, he strongly argued, was that no powerful nation was willing to serve as the importer, the lender, and the defender of the weak in troubled times, until it was too late. The result, Kindleberger gravely noted, was depression, aggression, unemployment, and ultimately war.

Many thoughtful observers worldwide are troubled by the Trump administration's conscious abdication of what were long regarded as key responsibilities of global leadership.

President Trump led the United States out of the TPP multilateral trade agreement only days after taking office. He also cancelled U.S. participation in the COP-21 environmental agreement, and failed to personally re-affirm key U.S. Article 5 commitments to NATO.

Trump has enthusiastically cultivated U.S.-Japan, U.S.-China, U.S.-Saudi, and U.S.-Israeli bilateral relations, to be sure, but has shown little interest in nurturing international institutions themselves.

Meanwhile, Chinese President Xi Jinping has taken exactly the opposite approach. At Davos in January, just as Trump was about to enter office, he rhetorically embraced free trade.

At the Belt and Road Forum last month in Beijing, I personally heard him on multiple occasions laud both sustainable development and the COP-21 environmental agreement, while attacking income inequality and promising increased Chinese support for poverty eradication worldwide.

Over the past six months, as Xi embraces multilateralism and Trump retreats to a defensive bilateralism that has been China's traditional approach to the world, Beijing and Washington seem to be reversing traditional roles.

How far can this go? Is China the new stabilizer in world affairs that Kindleberger sees the world as requiring? What of the American role?

Even once Trump is gone -- in six months, four years, or whatever -- can his successor in Washington repair the damage to America's leadership role that this incumbent President has wrought?

To address these crucial questions, we need to contrast classic American globalism to the new Chinese variant, to see what is being lost under Trump, what might be provided by Beijing in its place, and what really needs to be restored.

Classic American globalism is epitomized most eloquently and succinctly in the 1961 inaugural address of John F. Kennedy. Those historic words ring across the years in their idealism, multilateralism, and welcoming acceptance of America's global leadership role.

Kennedy sought, in his words, "not a balance of power, but a new world of law, where the strong are just and the weak secure and the peace preserved."

He pledged "a long twilight struggle against the common enemies of man: tyranny, poverty, disease, and war itself." He stressed cooperation. And he committed the United States to "pay any price, bear any burden, oppose any foe" to achieve its idealistic ends.

China's globalist conception, as Xi Jinping has recently presented it, is more modest and less legalistic than Kennedy's formulation, but does contain a few similar elements.

It suggests that China must seek to lead in achieving common human ends, which Xi considers to include economic prosperity, environmental protection, and eradication of poverty.

There is little discussion of the human freedoms that Kennedy stresses so strongly, or of alliance, and no commitments to defend others.

Xi's formulation avoids explicit geopolitics. There are, however, concrete commitments to development assistance, in the form of the Belt and Road Initiative, that rival or exceed those of the U.S. Marshall Plan in the early post World War II era.

Although China's new globalism and the classic American variety do have some common dimensions, the differences, to my mind, are far greater.

China's globalism is a kind of "infrastructure globalism" or "construction globalism," focused on building roads, railways, ports, and electricity grids. It provides distributive benefits, often quite liberally, to participants in the BRI, but often in non-transparent fashion.

There are no transcendent operating principles provided. The environmental appeals come through clearly in Chinese rhetoric, but it is not clear how operational they would be in practice, given the increased economic growth, not to mention road, rail, and air transport activity unleashed by the proposed new BRI infrastructure spending.

Linkages to Chinese geopolitical ends also remain tacit, even if unstated. Since China is in the heart of Eurasia, a literal "Middle Kingdom," increased continental connectivity naturally provides it with economic and geopolitical benefits, even if no explicit strings are attached.

America, in contrast to China, does not lie in the heart of a large, underdeveloped continent. It is a maritime power, whose economy has a global reach. Its globalism, not surprisingly, is not as geo-economically linked as China's Belt and Road Initiative, and is conversely more abstract, rule-oriented, and legalistic than China's version.

For a kindred maritime power like Japan, which cannot easily benefit from enhanced connectivity on large continents, the American version seems naturally more congenial, although participating in the distributive largesse of China's BRI must surely be tempting.

The question is whether America's classic version of globalism can survive the clear damage that Trump's revisionism is inflicting on it.

I am modestly hopeful. In the environmental area, American cities and states, led by California's governor Gerry Brown and former New York mayor Michael Bloomberg, are working to preserve the principles of COP-21.

In the realm of international trade, Japan's efforts, together with Vietnam and others, to preserve the essence of TPP are important -- many Americans still agree with the concept, and China is unlikely to replace the United States as a free-trade pillar, due to its inability at present to support the intellectual property, labor, or public corporate provisions at the core of the TPP agreement.

In time, the United States will come back to a variant of the original proposal, even if under a different name, perhaps through the Pence-Aso bilateral dialogue. China should be welcome to join, but not by undermining the high-quality existing agreement itself.

In the long run, the world may well fashion a hybrid globalism that merges the American and Chinese variants. The world needs better infrastructure, and China's "construction globalism" could help provide it.

It also, however, needs clear economic rules and a modicum of transparency. That is where the strengths of classic American "rule-based globalism" are enduring, even if the world today may be less idealistic, law-abiding, and peaceful than John F. Kennedy hoped for nearly three generations ago.

(Kent E. Calder is director of the Reischauer Center for East Asian Studies at SAIS/Johns Hopkins University in Washington.)