Until the global financial crisis, few in the United States believed the country was in decline. A minority now recognize this might be the case. The challenge to America’s position as premier global power comes from China. The fact it is only a developing country, with an economy much smaller than America’s and far less advanced, persuades many than this is a distant prospect.

China, though, is growing very fast, and since the financial crisis it has massively outperformed the United States.

Goldman Sachs has projected that the Chinese economy will overtake the United States in size in 2027 and by 2050 be twice as big. We are not talking about any time imminent when China will surpass America, but rather a process which will see China emerge as a great global power and the United States will find itself no longer dominant in the way it has been for more than half a century.

This is a prospect that the United States will find very difficult to imagine, let alone adjust to. Denial will probably be the dominant reaction for a long time to come.

In a small way, however, the process of adaptation has already started. The United States is in debt to China and, as everyone knows, you can’t treat your banker with disrespect.

There is now a realization in Washington that the U.S.-China relationship matters more than any other. But there is still a reluctance to acknowledge that America will have to adopt a different attitude to China, that it must treat the latter as an equal rather than, as hitherto, a supplicant.

In any future reform of the international economic system, for example, China will be a very powerful voice which the U.S. cannot ignore or dismiss. Chinese interests will have to be respected and taken into account.

The shift in U.S. attitudes, however, will have to go much further than this. There has been an underlying assumption that China will ultimately become a Western-style country. This is an illusion.

Certainly China has learned much from the West, but it is sheer hubris to believe that it will become like us. Countries are shaped by their history and culture as much as by markets and technology, and China’s history and culture are profoundly different from those of the United States (or any other Western country, for that matter).

This is something that the American ruling elite has given barely any thought to. But if we want to understand China and how it is likely to behave then we have no choice other than to address this issue. If we don’t, we will keep getting China wrong, unable to anticipate either its behavior or its trajectory.

The truth is that Western predictions about China have long been poor; in the future, getting China right is going to matter a lot more. The great challenge facing American policy-makers is to understand how China is different.

Let me give an example. China may call itself a nation-state, but it is primarily a civilization-state. The Chinese think of themselves as a civilization rather than as a nation.

As a civilization-state, China has two characteristics. First, it dates back at least 2,000 years, the oldest continuously existing polity in the world. The sheer age of China has myriad consequences, shaping its sense of ethnicity, the attitude towards the state and the sense of what it means to be Chinese.

Second, it is a huge country, both physically and demographically, which embraces great diversity. Westerners wrongly tend to think of China as homogeneous; it would be impossible to govern such a large country in a highly centralized way. Indeed, contrary to conventional wisdom, a civilization-state requires and embraces much greater diversity than a nation-state.

The rise of China – a phenomenon still in its relatively early stages – requires the United States to treat it differently and to understand the ways in which it is and will remain profoundly distinct from itself. This will inevitably challenge the traditional American belief that its values, norms and arrangements are of universal application. This will not be true in the case of China.