An "inflection point" in mathematics occurs when there is a change of curvature, say from concave to convex, at a particular point on a curve. There is now, at this particular point of time, an inflection point occurring in China's diplomacy, as the country changes from being reactive to proactive in its international relations. Future historians may characterize this transformation as one of the defining geopolitical trends of the first half of the 21st century.

Many foreigners worry, openly or privately, about what a strong China may do. The so-called China Threat is real in that many foreigners believe it to be real. But do these people know the real China? Deng Xiaoping, China's "Paramount Leader" who initiated reform and opening-up in the late 1970s, said famously that China should "hide our capabilities and bide our time".

Has China's "time" now come? President Xi Jinping has given his clearest directive for China's foreign policy and it is certainly more engaged with the world. Speaking to senior Party officials late last year at a top-level conference on foreign affairs, the first in eight years, Xi described China's new diplomacy.

Articulating the "strategic objectives and principal tasks of foreign affairs work", Xi stressed safeguarding China's core interests, crafting a conducive international environment, and hastening the nation's emergence as a great power. China, he said, should conduct "diplomacy as a great power" in an increasingly "multipolar" world - "making friends and forming partnership networks throughout the world" and "striving to gain more understanding and support from all countries" for the Chinese Dream.

China cannot compete for global leadership with power alone. Economic and military strength, while necessary, are not sufficient. There must also be moral and ethical aspects to China's rise. China, Xi asserted, should "see to it that equal importance is attached to justice and benefits, stress faithfulness, value friendship, carry forward righteousness, and foster ethics".

At a senior session on regional free trade, Xi called for China to "participate and lead, make China's voice heard, and inject more Chinese elements into international rules". To effect such historic change to the world order, Xi is reshaping the diplomatic landscape with "active engagement". From climate change to international peacekeeping, he is changing China from a sometime reluctant follower to an often creative leader. Xi's China has reemerged as a great power and there is no turning back.

What is Xi's grand vision for China? The world is watching; many are hopeful, many are fearful. Some wonder about Xi's intent. But there is now no need to wonder; he has made his intent clear in his new book Xi Jinping: The Governance of China.

For China to fulfill its potential as a global leader, it must gain the world's respect for its principles and philosophies, not only for its economy and military. This involves appreciation for China's self-determined "road of development" and for its political system, particularly the perpetual leadership of the ruling party.

This is a larger topic but such appreciation can develop only with a kind of convergence, where China's political system continues to reform, with increasing transparency and freedoms, and where foreigners come to understand that pragmatic competence managing China's complex society trumps idealistic ideologies of multi-party democracies.

In my dream of a post-adversarial world, China assumes increasing responsibility for world peace and prosperity, which includes opposing regimes that trouble their own people. In seeking the moral optimum, China may have to tear up old scripts.

For its part, the United States should reject the Cold-War mentality of "containing China" as being both archaic and self-defeating. Of course, there remain areas of contention - balance of trade, human rights, territorial disputes - but different political systems should not be one of them. Politico-economic theories constructed in the 18th and 19th centuries have little utility in the 21st century, where most nations optimize free markets and government regulation that by nature can be neither generalized nor static.

In today's world, the real conflict is not between opposing political systems but rather between the forces of modernity, competence and development on the one hand, and those of ignorance, exploitation and oppression on the other.

China's increasing engagement with global diplomacy should be celebrated.