So far, there have been no such defining moments in 2007. Perhaps we should be grateful for that, since world-shaking events are often sudden acts of shocking violence. But it makes it both trickier and more interesting to carry out my annual end-of-year exercise – listing the five most important events of the past 12 months. Nonetheless, I intend to try. If you want to make sense of world affairs, it is useful to identify the most significant events. Also, I like making lists. So here goes:

January: the surge. It is too soon to tell whether US President George W. Bush’s decision to increase the number of American troops in Iraq will go down as the moment when the US began to turn the situation around; or just a last, failed throw of the dice. The big questions still have to be answered. Is a civil war in the offing? What will happen when America withdraws its extra troops?

Even so, it is already clear that the surge was a major event. It demonstrated that Mr Bush had decided to reject the Baker report, which was widely assumed to be America’s exit strategy. By the end of the year, the drop in violence in Iraq – in particular, in Baghdad – had begun to win round some of the surge sceptics. Even the leading Democratic candidates for the presidency are refusing to promise that all US troops will be out of Iraq by 2013. The surge showed that America is in Iraq for the long haul.

The Russian president signalled a new mood in his country’s foreign policy with an extraordinary and angry speech, in which he accused the Americans of “an almost uncontained hyper use of force . . . that is plunging the world into an abyss of conflicts”. The Putin speech heralded a year in which Russia has been increasingly assertive on everything from missile defence to Kosovo to arms control and energy policy. A high oil price and a booming domestic economy have boosted the government’s confidence. Assertiveness overseas has been matched by growing authoritarianism at home. Russia thinks it is back and it wants the world to know.

August: the credit crunch. America’s housing-lending crisis emerged during the summer and is still unfolding. It may yet turn out to be “just” a financial and economic problem. If that turns out to be the case, the credit crunch would not deserve a place in a list of the five most important geopolitical events of the year. But American consumers’ ability to keep buying has been fundamental to the world economy in recent years. If the subprime problem puts a stop to that – and leads indirectly to further falls in the value of the dollar – there will be global political implications. Chinese-US relations will deteriorate; the European economy will come under pressure, as will the entire global trading system. America will find it harder to pay the bills that come with being the world’s policeman. It is worth remembering that the backdrop to the political turmoil of the 1930s was the Wall Street crash of 1929.

. Yes, there were plenty of reasons why this was a bit of a mirage. Only 2.2 per cent of the company was floated on the Shanghai Stock Exchange. The company’s valuation at more than $1,000bn (£496bn) – double the value of America’s Exxon Mobil – certainly reflected the bubble in Chinese stocks. Within a month, PetroChina had lost a third of its value (although this still made it worth more than Exxon). Still, the fact that the world’s most highly valued company is now Chinese has an undeniable symbolic punch. And PetroChina is no fluke. Four of the 10 most valuable firms in the world are now Chinese.

. If you are listing events of global significance, why pick one country rather than another? I could make a case for the election of President Nicolas Sarkozy in France; or the resignation of Tony Blair in Britain; or the fracturing of the Palestinian Authority; or Hugo Chávez’s referendum defeat in Venezuela; or the AKP’s election victory in Turkey, which ended that country’s constitutional crisis and entrenched civilian rule; or, indeed, for long-term trends that made headlines – such as the rise in the oil price and the melting of the Arctic.

Instead, I have gone for General Musharraf’s declaration of a state of emergency. Pakistan is the country where all the trickiest issues in American foreign policy seem to come together. It is US policy to promote democracy, to attack terrorism and to crack down on nuclear proliferation. Yet in Pakistan the US finds itself allied to a military regime, a nuclear proliferator and an uncertain and ambiguous ally in the wars on
terror and on the Taliban in Afghanistan. Gen Musharraf’s decision to hang on to power and lock up the country’s judges was a severe embarrassment to the west – and a testament to just how unstable Pakistan remains. But America has stuck with him because all the plausible alternatives seem worse.

Is there a common theme linking these five events? Clearly. The link is the growing strain on the world’s sole superpower. America is locked into a draining and demoralising war. Russia, an old adversary, is becoming more assertive. China, a new rival, is on the rise. Pakistan, a vital ally, threatens to fall apart. The US economy is under more strain than for years. Happy new year.