Since the end of the Cold War in the late 1980s and early 1990s, it is widely accepted that the United States has been the world's sole superpower. This is based on two indisputable facts. The first is the size of its economy, which has been utterly dominant over this period and constitutes approximately a quarter of global GDP. The second is the size of its military. The United States has the army, navy and air force powers to project its force over the rest of the world. It spends more on defense than the next 10 countries put together. It has dominance in technology and in capability. Uniquely, it has the capacity to be involved in security issues throughout Europe, Asia, Australia and Africa. It is the one power with this kind of global reach.
In the last decade since the tragedy of September 11 in 2001, however, the United States' dominance has been questioned. It has been stretched with two costly wars in Iraq and Afghanistan, which have lasted longer than expected and proved more complex in their outcomes both politically and economically. President Barack Obama made it clear upon his election in 2008 that he wished to see a phased withdrawal of all U.S. troops from Afghanistan, the last ongoing military action by U.S.-led forces. This is due to happen by 2015. In addition, the U.S. economy has been under immense stress because of the sub-prime crisis which started to appear in 2007, and decimated the country's finance sector and its exports in the next two years.
The United States has returned to steady growth in 2012 and the first two quarters of 2013, and looks likely to post stronger growth than expected this year. However, Vice President Joe Biden admitted during a meeting with Chinese Vice Premier Wang Yang at the China-U.S. Strategic and Political Dialogue in Washington D.C. in July that the economy is still suffering large structural challenges, with high levels of debt and the continuing need to create jobs and support manufacturing.
Commentators are keen to talk of this as an era of U.S. decline, and of there now being a bipolar or tri-polar world. In 2009, in particular, during the G20 Summit held in London and before President Obama's visit to China later that year in November, there was talk of a G2, with China as the world's second most powerful nation. Much of this was based on the fact that aggregately China has become the world's second largest economy, and one of the main sources for global growth, in the last five years. It is natural to impute China with an enhanced and prominent global rank.
However, Chinese leaders at the time were keen to stress that G2 was not something they recognized or aspired to. Many of them pointed out that China remained a country with per-capita levels of wealth that put it around number hundred in global rankings. So why would it wish to push itself toward a role now taken by the United States? Its priorities remained attending to its own internal issues of growth, sustainability and balance.
Being number two is never easy in any system. There are always suspicions about how second ranking powers or people harbor ambitions to replace the number one in the future. There is a natural feeling that no one can stay in the top position forever, and that there is an inbuilt proclivity to decline in the top players after their moment of glory. Many worry that this decline might be marked by unrest, tension and conflict, as happened when the UK was replaced by Germany and then the United States in the early part of the 20th century, an event which unleashed conflicts in Europe and resulted in two massive world wars. The world cannot bear the costs of this sort of transition. That, at least, seems clear.