Last month's spy-plane incident between the United States and China inadvertently highlighted South China Sea territorial disputes as a focal point of possible international confrontation. Although the incident is viewed primarily through the lens of U.S.-China relations, it demonstrates the international stake that nonclaimants have in upholding the principles of freedom of navigation in international air space and waters of this vital waterway -- over half of all the world's oil now passes through the South China Sea from the Middle East to Asia.

The incident highlights the increasing likelihood of accidental military conflict as countries in the region modernize their military forces. Many Southeast Asian neighbors are concerned that China's naval and air force improvements will eventually shift the balance of power to enforce its disputed claims decisively in Beijing's favor. China's inconsistent interpretation and application of the U.N. Convention on the Law of the Sea to its South China Sea territorial claims and Beijing's recent challenges to an Australian flotilla in international waters near the Taiwan Strait appear to justify such concerns.

However, the most serious immediate threats to the South China Sea result from a vacuum of responsibility rather than hegemony by a dominant regional power. The core of the dispute remains state sovereignty -- attempts to enforce disputed, overlapping claims could trigger a conflict that no one seeks. In addition, serious environmental problems resulting from a possible oil spill, damage to reefs and vital marine habitats through construction and from illegal fishing or the rise of piracy constitute growing threats to human security.