Meanwhile, senators from both parties say the United States needs to send military vessels and aircraft within the 12 nautical mile territorial sea limit to make it clear that it does not recognise China’s claim to the islands. Senator McCain said: ‘[not doing so] is a dangerous mistake that grants de facto recognition of China’s man-made sovereignty claims’.

But these calls for the US military to try to test China’s claims are ill-advised, and even dangerous.

China occupies at least seven features in the Spratlys: Cuarteron Reef, Fiery Cross Reef, Gaven Reefs, Johnson South Reef, Mischief Reef, Subi Reef and Hughes Reef. It has undertaken construction on all of these. But it is not clear that China does or will claim maritime zones from submerged features that it has ‘reclaimed’.

China does claim sovereignty over all the features in the South China Sea, including legal islands that can generate a full suite of maritime zones but are claimed and occupied by others. Examples include Taiping (claimed by Taipei), Spratly (Vietnam) and Thitu (the Philippines). Of course their sovereignty and boundaries with other coastal state claimants are disputed and must be negotiated.

China could argue that the ‘artificial formations’ are within its jurisdiction by virtue of its exclusive economic zone and continental shelf claims from these legal islands. This jurisdiction carries with it the exclusive right to construct and to regulate construction, operation and use of artificial structures. Such structures are entitled to reasonable safety zones around them, usually — except under special circumstances — not exceeding 500 metres.

China might argue that these safety zones include the airspace above them. This would explain its warnings to foreign military aircraft not to violate the airspace.

Fiery Cross Reef and Cuarteron Reef may also be legal islands, meaning they can sustain human habitation or economic life of their own. But only Subi, Hughes and Mischief Reefs were definitely neither islands nor rocks before China’s construction activities. Although there is some question about Gaven Reef, the others occupied by China were at least legal rocks entitled to 12 nautical mile territorial seas.

Penetrating their airspace would be a direct and public challenge to China’s claim of sovereignty. China argues that sending a warship into its territorial sea violates its legal regime requiring prior permission to do so. Of course, China’s position is not consistent with the United Nations Convention of the Law of the Sea (UNCLOS). But if the US warships were to enter China’s territorial sea without permission, it would violate Chinese law and publicly embarrass China’s leadership.

Sailing a warship or flying a warplane into or over a country’s territorial sea to demonstrate the right of free navigation could also be construed as a threat to use force. At worst, this is a possible violation of the UN Charter and UNCLOS; at best, it is not a positive example of peaceful resolution of disputes. It has even been suggested that such provocative demonstrations of freedom of navigation may not be the continuous and expeditious movement required for ‘innocent passage’ in the territorial sea allowed by UNCLOS.

If the US government conducts freedom of navigation operations in the area, it should be with continuous and expeditious passage or overflight within 12 nautical miles of Subi, Hughes or Mischief Reefs. In that case, China may ignore the provocation as it has not publicly claimed territorial seas around these previously submerged features. But to demonstrate its professed ‘neutrality’, the United States should also physically challenge other claimants and occupiers of artificial formations constructed on submerged features.

But it does not appear that these lawmakers are concerned with the legalities surrounding these issues. They want chest-thumping action and they want it now, regardless of legal ‘niceties’. To them, the main purpose behind a public American challenge would be to demonstrate Washington’s will to defend freedom of navigation and to dissuade China from any further ‘aggressive’ actions and claims in the South China Sea.

But this is dangerous. Doing so may well backfire. What if Beijing pushes back by confronting the warships and aircraft with its own? Then Washington would be faced with a dilemma of its own making. It can either ‘put up’ and risk escalating a crisis or ‘shut up’ and stand down — which would show weakness, damage its reputation and generate doubt about its commitment to its friends and allies. Moreover there is always the possibility of an accident or a miscalculation.

US politicians may underestimate the zeal of China’s nationalist movement and the leadership’s need to accommodate it. China has publicly positioned its sovereignty and claims in the South China Sea as a matter of national dignity and redemption for its ‘century of humiliation’. This makes it very difficult for China’s leadership to back down on these issues.

Thus the action that many in the United States are calling for could result in serious international conflict. Is it worth the risk? Some Southeast Asian nations might not think so. It is clear that the US Department of Defense is aware of this potential dilemma and is proceeding cautiously. According to David Shear, the US Assistant Secretary of Defense for Asia and Pacific Security Affairs, ‘freedom of navigation operations are one tool in a larger tool box that we’re going to need to use’.

Despite the US concerns, China has never threatened commercial freedom of navigation and is highly unlikely to do so in peacetime. It is not in its interests. The US government well knows this and yet is seemingly willing to risk conflict by conflating the right of commercial freedom of navigation with .the ‘right’ of military vessels and aircraft to undertake provocative intelligence probes.

But whatever the US government does, it will not placate the anti-China crowd. Decisions must be driven by larger, longer-term goals. It is critical that at this juncture US decision makers remain calm, cool, collected and courageous.

Mark J. Valencia is an adjunct senior scholar at the National Institute for South China Sea Studies, Haikou.

A shorter version of this article was originally published here in the South China Morning Post.