Asia's Nightmare Scenario: A War in the East China Sea Over the Senkakus

America & Japan vs. China. Who wins?

It is clear that an armed clash between Japan and China over the Senkaku/Diaoyu islands is a real possibility.  If that happens Washington would face a very serious choice.  Failing to support Japan militarily would fatally weaken the US-Japan alliance, torpedo President Obama’s ‘Pivot’, and undermine America’s whole position in Asia.  But supporting Japan would mean going to war with China.  Whether that would be wise depends, as much as anything, on how a US-China war over the Senkakus would play out. 

Of course no one knows for sure.   There has not been a serious maritime conflict for decades, nor war between two nuclear-armed states so we cannot be sure how the fighting would go.   Nor do we have any real experience of war between nuclear-armed states, so that factor too adds to uncertainty.  But there are some broad judgments that can be offered.  If these judgments seem even moderately likely to be right, the implications for America’s choice about war over the Senkakus are rather sobering.  They suggest that this would be a war that America would not win, could not control, and should not undertake.  And that of course has huge implications for America’s position in Asia.

Suppose that fighting starts between China and Japan with a small armed clash near the islands, in which losses are sustained by both sides.  It is possible this kind of incident could be quickly contained without further fighting, but only if both Tokyo and Beijing acted with tact, forbearance and political courage.  No one would bet on that, so it is at least equally likely that the clash would escalate, and if so Japan would quickly ask America to help.

What happens next if America joins the fight depends first on the strategic aims of each side?  China’s primary aim might be to land forces to take control of the islands, and at the minimum it would want to exclude Japanese and US forces from the air- and sea-space around them.  America’s and Japan’s aims might well look the same.  Tokyo might decide that the time had come to put its control of the islands beyond dispute by stationing forces on them, and at a minimum it would want to prevent further challenges of the kind we have seen recently by excluding Chinese forces from around the islands.

What operational objectives would flow for each side from these strategic aims?  Let us first suppose that each side decides to limit the geographic scope of the conflict to the areas around the disputed islands.  To achieve their primary aims by deploying and sustaining occupation forces on the islands, either side would need to establish a high degree of sea and air control around them. That is likely to prove impossible for either of them: neither China nor the Allies have any serious chance of achieving the sea and air control required to securely deploy and sustain occupation forces on the disputed islands against the other side’s formidable sea and air denial capabilities.  So as long as both sides limit their operations to the area around the islands, neither would be able to take control of the islands by establishing forces on them.

The situation is much less clear when we look at the two side’s minimum aims.  To prevent each other operating near the disputed islands they would only need to impose sea and air denial around them.  Each side could probably deny the waters surrounding the islands to the other’s surface forces. Neither side could prevent the other sustaining a substantial submarine presence there.  But a battle for air superiority over and around the islands might be more evenly balanced.  Allied advantages in quality and perhaps in tactics could be offset by Chinese advantages in numbers and proximity, leading to a protracted and inconclusive air campaign in which losses on both sides would be quite high.

This suggests that as long as operations were limited to the immediate area under contention, the most likely outcome would be an inconclusive stalemate: both sides could deny the waters around the islands to the other’s surface ships, but neither can exclude the other’s submarine and air forces from the disputed area.  It is hard to see how either side would consider this a satisfactory basis to conclude hostilities. Neither would have to improve their position in relation to the islands enough to justify the costs of the fighting. Both would be trapped in an indefinite and costly campaign, especially in the air, with no way to end the conflict.  Quite apart from any other considerations, this would prolong the extraordinary disruption of the conflict to each side’s economy, and convey a message of weakness to each side’s public.  

This means both sides would have strong incentives to seek a quicker and more decisive result by broadening the conflict beyond the disputed area itself.  That could happen in several ways.  Some people have suggested that America could prevail in this kind of situation by imposing a distant blockade of China which would bring its highly trade-dependent economy to its knees. Others have suggested that cyber-attacks or attacks on China’s satellites could compel China to back off. Certainly Washington has these options, but so does Beijing. America is just as vulnerable as China to attacks on its sea-borne trade, cyber systems and satellites, and China’s capacity to mount such attacks is quite formidable.  Moreover China may have options to damage America’s economy through its immense holdings of US debt.  This suggests that on balance neither side would see much to gain in opening these kinds of new fronts.