THE US presidential election campaign has been fascinating but whoever is in the White House next year won't be the most important and powerful man in the world.

That man will be the new leader of China, and we should know who he is by the end of this week.

The current President of China, who is also the Communist Party Secretary, Hu Jintao, is about to step down. The heir apparent is Vice-President Xi Jin Ping, a 59-year-old chemical engineer who once laboured in an agricultural commune. (Imagine a UK leader who was an engineer and had once laboured in a commune. We seem to go in for ageing student politicians, PR men or, if we get marginally more lucky, lawyers.).

While there has been quite a lot of discussion about Xi Jin Ping, much of it is speculation, because the corridors of power in China remain dark, obscure places. Even so the western obsession with Messrs Obama and Romney seems a tad overcooked when you consider that next year, and beyond, the leader of China will be a considerably more significant global figure than whoever is in the White House.

I've heard various correspondents and China experts talking about Xi Jin Ping and have also heard his name pronounced in various different ways. (I am assured the correct pronunciation is She-Jen-Ping). This might seem a trivial point, but imagine the derision there would be if someone referred to Obeema or Ramney. For whatever reason, the West remains obsessed with the US and we have not yet come to a collective and settled understanding that China is the most important country on our planet. The US is still culturally and militarily powerful and its navy still protects the shipping lanes on which world trade depends. Its economy is technically larger than China's. But not for much longer. A mere 12 years ago, it was eight times bigger.

It's time that we faced up to America's grievous decline. I am not anti-American, but like so many countries in Europe, the US is mired in debt. This may not be a huge problem for people of my generation but my goodness it's going to be a burden for future generations in the West.

The legacy that my generation is handing on is, quite frankly, pathetic. Take the UK. The current Government may be making creditable efforts to grapple with our deficit but even, and this is unlikely, if the deficit has been reduced to zero by the next General Election in 2015, our national debt, a much more serious problem than the deficit, will still be colossal. This massive overhanging burden of debt will overshadow the lives of one, two or even three coming generations.

Meanwhile the most spectular phenomenon of this young century has been the amazing economic growth, capitalist-style, in a country ruled rigidly by Communists. I know that this growth is faltering a little, and that China faces significant problems such as growing internal dissent, endemic corruption, and social division leading to potential instability. It will be fascinating to see how Xi Jin Ping, supposedly a moderate, progressive man, deals with these looming clouds darkening the red skies.

But he will be swimming in deep water; China's economic power is, and will be for the foreseeable future, gargantuan. Western leaders, including US presidents, must paddle around, ever more feebly, in the shallows.

When the men in black suits walk in carefully orchestrated order along the long red carpet at the Chinese Communist Party Congress later this week, they will hand over power to their new leader, the man who will have the economic destiny of the entire world in his hands. The US still has military might, but the economic power is in the East, and how. The most worrying thing for the West will be if China tries to divert growing internal tension with rapid military expansion linked to a bellicose foreign policy. There is no sign of that as yet, but we should be prepared.