While the world is preoccupied with upheavals in financial markets and the US primary elections, we should not forget a strategic issue of enormous importance. China and the US face a momentous choice about whether to proceed in the decades ahead as competitors or collaborators.

Many forces are driving them apart. But the context for making the right decisions should be an understanding of the "new commons". These are areas of common interest that all nations depend on - the economy, open seas and skies, space and the internet. We should cultivate these commons in such a way that China and the US become strong partners.