Peter Jennings is right to point out ^[1] that siting surface-to-air missiles (SAM) on Woody Island in the Paracel Islands is a strategic game-changer for the South China Sea. It’s also the logical corollary to building fighter-length runways ^[2] and installing long-range radar ^[3] on reclaimed islands. In this great game of grandmother’s footsteps, it confirms what’s in store for the island bases China is building much further south, in the Spratly archipelago.

But passing over the mechanics of maritime and territorial disputes in the SCS, does China’s strategy make strategic sense? Ultimately, will island runways, jet fighters, radar and SAMs enable China to assert its territorial and maritime claims? If the bottom line is ever reached—and brinkmanship revolves upon perceptions of bottom lines—could China’s chain of unsinkable aircraft carriers ever prevail?

The principal challenge for China is that the further it presses down into the SCS, the more it requires its forces to transition from ‘air-sea denial’ capabilities to ‘air-sea control’. In strategic terms, these are quite different propositions. The first implies the power to prevent others from doing as they please. The second implies the power to do as you please because others can’t stop you.

Unfortunately for China, when the geography of the southern SCS is combined with the realities and trends of military technology, the chances of being able to assert control—in particular over the Spratly archipelago, but more generally over the whole of the nine-dash line—become increasingly remote.

In practical terms, China can build any number of radar-, fighter- and missile- equipped islands, but their value as bases for exerting air-sea power depends on China’s ability to keep them supplied. China must have the power to control air and sea communications between islands and its mainland or those military assets become potential liabilities. (While there’s a qualitative difference to air and sea supply lines, in practice that’s just a matter of endurance.)

However, as the political topography ^[4] of the Spratly Islands makes clear, the potential for antagonists to interdict both air and sea passage to China’s Spratly bases is almost limitless. The Philippines and Vietnam have outposts which, if also equipped with radar, SAM batteries, and surface-to-surface missiles, could isolate Mischief Reef and Subi Reef—both scenes of fast-paced runway construction.

With its own islands to the northeast and southwest, Vietnam alone has the capabilities to blockade Fiery Cross without putting a vessel in the water or an aircraft in the sky. Militarisation would take days, involve better kit (thank-you Uncle Sam), cost little compared to China’s gigantic dredging and construction operations and exert punitive levels of risk on Chinese resupply.

So, in theory at least, China’s escalations in SCS can be countered with instruments of blockade at a relatively low cost.

The orthodox answer, for China, is naval air power. With sufficient naval forces to guarantee resupply, China’s airfields become viable propositions in a conflict situation. Sure enough, China’s aircraft carrier program is ramping up. On 31 December, Xinhua confirmed ^[5] a second 50,000-ton vessel. With no hiccoughs, the Peoples Liberation Army Navy (PLA-N) may be able to operate 30 fixed-wing fighter and strike aircraft by 2019, or double if its progenitor—Liaoning ^[6]—magically transitions ^[7] from its current training and technology-demonstrator role.

To be sure, the traditional and primary role of aircraft carriers is to assert air-sea control, but the theoretical value of China’s emerging carrier fleet is far removed from its practical value in the cramped waters of SCS. In a conflict situation, PLA-N has to be certain its carriers and escorts will prevail before it can risk sending them in. However, the opportunities to attack a carrier fleet in SCS are almost limitless.

The logic is circular but inescapable: the carriers are the means to acquire control of communications, but only if they can definitely be protected. And the US navy has spent the best part of a decade grappling with the realisation it can’t easily protect its carriers in comparable environments against today’s Anti-Access/Area Denial (A2/AD) weapons. It has now reformulated ^[8] its doctrine accordingly.

China cannot sail a carrier fleet into a hostile southern SCS without taking lunatic risks. And this situation won’t change any time soon. We live in a technological age when the A2/AD weapons are far cheaper than the defensive weapons required to defeat them. China was on the winning side of this cardinal trend with its carrier-killer missiles ^[9]. By moving to a position where it needs to assert command, it has started to play a much more expensive—and possibly losing—hand. Its adversaries will arm their islands to the teeth with A2/AD weapons, including especially sea-skimming missiles.

Thus, the logical and probable end point of militarisation in SCS will be a mutualised ability to deny access. What all sides will know is that at the flick of a military switch, the salient areas of SCS would quickly become the air-sea equivalent of trench warfare’s no-man’s land. This standoff would halt navigation in SCS. But with huge air-bases it cannot re-supply and flagships it cannot sail, a standoff would be a political-military disaster for China.

In strategic terms, the country is setting itself up for humiliation.

It’s impossible to know how China’s antagonists are calculating the situation and the optimal time, place and circumstance to precipitate a direct challenge. But if this strategic analysis is correct then it may pay dividends to let China’s expensive, diplomatically alienating and strategically unsound policy run for quite some time. As the Transvaal President Kruger said ^[10], when asked why he didn’t take forestalling action against jingo Brits: ‘You must give the tortoise time to put out its head before you can catch hold of it.’