Reuters reports on an escalation in China's dispute with Vietnam over control of contested waters in the South China Sea, with a Chinese state-owned oil company moving an oil rig into territory claimed by Vietnam:

On Sunday, Vietnam said the coordinates of the rig put it in Vietnam's exclusive economic zone and on its continental shelf, about 120 nautical miles off its coast.

But, like other Asian nations involved in territorial disputes with China, Vietnam appears to have limited options when dealing with the emerging superpower.

The Philippines said last month that the United States had a treaty obligation to help in case of an attack on its territory or armed forces in the South China Sea, although Obama did not say categorically that Washington would do so.

It's not quite right to say that Asian nations have limited options in dealing with China. Vietnam, for instance, has beefed up its own maritime defences and its relations with Russia. And as Richard Javad Heydarian argued earlier today, the Philippines is inching closer to the US in response to China's moves.

But the lingering question for both these countries, and for others that have territorial disputes with China, is whether they could count on these great powers if they needed them (this week's issue of The Economist tackles this very issue by asking 'What Would America Fight For?'). As the Reuters piece says, the US has stopped short of endorsing Manila's view that Washington is obligated to intervene in the event of a clash in the South China Sea. Of course any such intervention would be highly escalatory, and Beijing must be betting that it can keep these disputes just small-scale enough that Washington would decide the game is not worth the candle.

The other big question is why China has determined that escalations such as these are in its interests. Of course, we have to allow for the possibility that 'China' has made no such determination. We tend to think of decision-making in Beijing as being coherent and monolithic, but that's not always a safe assumption. The right hand does not always know what the left is doing.

But let's assume for the moment that China's growing assertiveness on territorial disputes is a conscious decision from Beijing's central leadership. If the ultimate aim is to assert China's influence in the region (in other words, doing what comes naturally to all great powers), on what grounds has Beijing determined that assertiveness on territorial disputes is the most effective means to that end? In fact, wouldn't China be better off with the opposite strategy, one of doing nothing except continuing to grow as a world economic power? If Beijing kept its defence spending stable in relation to GDP and did little to provoke balancing coalitions, it would still over time develop a formidable military and enormous economic pulling power. Those same forces would ensure a relative decline in US power in the region over the same period. Wouldn't those factors alone give Beijing the regional influence it desires in the long term? And wouldn't that be a cheaper and less risky approach?