Relations between China and the United States seemed to have worsened because of the US arms sale to Taiwan and a host of other issues. In the US, support for President Barack Obama's programmes appears to have weakened.

Has that encouraged the Chinese to talk tough? Are there developments within China that have led its leaders to move away from low-key responses and take higher profiles abroad?

Certainly Beijing's tone and the words it has used in public exchanges have been stronger than usual. Does this come from a shift in Chinese thinking?

I believe that China is not obsessive about what the US thinks, but it has always looked around in every direction. So I thought I should go through my checklist of what would appear to be the core global issues from the Chinese perspective.

China has carefully studied the rise and fall of modern great powers from the time they sprang out of the aggressive political cultures of the 15th and 16th centuries and re-configured the course of Atlantic history to the present.

Although the empires of the Western powers reached the Indian and Pacific Oceans, the real struggle among them remained in the Atlantic. It was not till late in the 20th century, after the empires were finally dismantled, that the centre of gravity of great power conflicts moved eastwards to Asia.

Chinese leaders know that China's greatest mistake from the 15th to the 20th centuries was to remain with its continental mindset while a fundamental shift had taken place in the world.

Chinese leaders are still struggling to find the right balance between their overland concerns and the threats to their maritime borders. But they know a great deal about nuclear weapons and are learning fast about cyberspace. On the whole, they now find it easier to understand what is necessary in order to ensure their security.

Recent geopolitical changes have occurred because China's rise has produced the view in the West that China is the only power that can resist Euro-American global hegemony. Other pockets of resistance in Africa, Latin America and the Middle East can be handled as local operations. Thus the attempts to induce, if not force, China to conform to the dominant norms.

The Chinese see this as a continuation of the ideological thrust that has been challenging China's sovereignty for the past 150 years. Their leaders note that this could ultimately be aimed at another regime change.

To them, the obvious manifestation of this thrust is the coming together of the US, Japan and India in the name of shared democratic values. This is feasible because modern military and communication technology has ensured that the Indian and Pacific Oceans are no longer too big for political cultures and patterns - the tussle between democracies and non-democracies, for example - once confined to the Mediterranean to replicate themselves in Asia. China realises that it has to be more watchful of such rivalries, for they may well threaten it.

In this context, China finds comfort in Asean's reluctance to join the ideological game. In its own interest, Asean has played a valuable role in reducing the sense of threat among the major protagonists involved in the region. Its efforts to minimise ideological thinking emphasising differences have been reassuring. China wants to help promote policies that can knit together those with similar goals in both the Pacific and Indian oceans.

In contrast to South-east Asia, China sees the regions to its north and west as posing persistent and intractable problems for its security and is determined to strengthen its defences along its borders with these regions.

My checklist of China's core interests becomes simpler when it comes to the country's internal goals. The hierarchy of its concerns has changed little over recent decades. The highest priority is still rapid economic development.

Two developments have pushed for change internally: the financial crisis in the West, where China's main markets are; and the damaging environmental degradation within the country. But China will change its policies gradually; the changes will not be panic-driven.

Beijing's concerns with internal stability remain unchanged. National attention has been directed at achieving social harmony, a clear admission that rapid economic development has led to inequalities beyond what can be tolerated by the Chinese people. The authorities know that there is widespread anger at the rampant corruption in official circles. Judicial and political reforms will continue, but the stress will be on caution. All future moves will continue to be deliberate and controlled.

China's key concern over the past century has been its sovereignty. The legitimacy of any Chinese government depends on its capacity to unify the country and preserve its borders.

Many lessons have been learnt from the period of turmoil that the Chinese people experienced, the most important being the country will always need development and order. Thus, the US and China may be talking less softly to each other today, but nothing fundamental in Chinese policy has changed to explain this shift.

The writer is chairman of the East Asia Institute, National University of Singapore. Think-Tank is a weekly column rotated among eight leading figures in Singapore's tertiary and research institutions.