When Indonesian Foreign Minister Retno Marsudi delivered ^[1] her traditional annual foreign policy review recently, she made a point of referring to last month’s separatist slaughter of 19 construction workers in rebellious Papua. ‘Indonesia’, she declared, ‘will not back down, not even an inch, when it comes to its sovereignty.’

What struck observers, however, was her failure to make the same point about the South China Sea now that President Joko Widodo has followed through on a two-year-old pledge to strengthen the country’s military presence on Natuna Besar, the largest of 272 small islands on the southern fringe of the disputed waters.

The closest land mass to an increasingly assertive China, the 1,720-square-kilometre island is being equipped with a sophisticated surface-to-air missile system, elements of a marine battalion and significantly upgraded air and naval bases.

Marsudi’s focus was interesting, given that the government has sought to keep Papua off the international agenda while trying to convince Melanesian nations in the southwest Pacific that Indonesia is treating the Papuans fairly.

Certainly, it reflected the shock that rolled through the security community over the 1 December massacre, believed to be the worst single case of bloodletting since the Free Papua Movement (OPM) launched a stuttering insurgency in the late 1960s.

But Marsudi’s failure to make more than a passing reference to the South China Sea was surprising—particularly when China now insists that it has a claim to so-called ‘traditional fishing grounds’ inside Indonesia’s 200-nautical-mile exclusive economic zone (EEZ).

Traditional fishing grounds are not recognised in the United Nations Convention on the Law of the Sea; but traditional fishing rights are, and they have already been the subject of successful bilateral negotiations between Indonesia and two of its neighbours, Australia and Malaysia.

When Jakarta produced an updated national map in 2017 renaming ^[2] the EEZ north of the Natuna Islands as the North Natuna Sea, the Chinese Foreign Ministry dispatched ^[3] a formal letter declaring that the two countries have overlapping maritime claims.

Changing the name, it said, had only complicated the dispute and threatened peace and security in the region—despite the fact that Indonesia is not a claimant to the Spratly Islands and doesn’t recognise any boundary issue with China.

After years of prevaricating, it was the first time Beijing had suggested that its claimed nine-dash line of historical sovereignty, which envelops most of the South China Sea and has no basis in maritime law, actually infringes on Indonesian waters.

The signs had been there for some time. After several incidents in the previous three years, tension escalated in March 2016 when the Chinese coastguard seized back a fishing boat detained in what it said was traditional fishing grounds.

What angered Indonesian officials is that two heavily armed Chinese coastguard vessels penetrated the country’s 12-nautical-mile territorial limit to force the return of the trawler, which had been caught by a fisheries protection craft deep inside the EEZ.

Two other Chinese fishing boats were intercepted in May and June 2016, but as far as is known there have been no further cases since then, an indication that Beijing may have decided to approach Indonesia differently from some of its smaller neighbours—at least for now.

That cuts little ice with feisty Indonesian Fisheries Minister Susi Pudjiastuti, who continues to accuse China of committing transnational crime by paying off Indonesian fishing boats to offload their catches onto Chinese motherships positioned just outside the EEZ.

Chinese fisheries suffered a setback late in 2014 when Pudjiastuti banned foreign fishing boats from Indonesian waters, saying they and their Indonesian partners had breached the terms of their joint venture agreements and cost the country billions of dollars in lost revenue.

Foreign policy has never been a Widodo strong suit, but his pledge to beef up Indonesia’s northern defences remains one of the centrepieces of his government’s determination to protect natural resources and to grow Indonesia as a maritime power.

Analysts believe the Indonesian Armed Forces (TNI) will deploy Norway’s advanced Kongsberg medium-range missile system (NASAMS) to the Natunas, providing an air defence umbrella covering more than 100 square kilometres.

The newly acquired weapon is based on Raytheon’s advanced medium-range air-to-air missile, or AMRAAM, which the US approved for sale to Indonesia in 2016 when its air force took delivery of an additional 24 refurbished F-16 fighters to boost its front-line air defences.

Natuna Besar may also become the base for some of the eight new AH-64E Apache attack helicopters which were sold to Indonesia on the strength of their perceived role in safeguarding the free flow of shipping through the Malacca and Sunda straits.

The government plans to lengthen the island’s 2,500-metre runway and to build more hangars and improved refuelling facilities, ready perhaps for the proposed purchase of C-130J Super Hercules cargo planes that can be configured for prolonged maritime patrols.

The air force is also likely to deploy unmanned aerial vehicles (UAVs) to the island to expand its reconnaissance abilities over the East Natuna gas-field and the busy shipping lanes that cross the northern approaches to the Java Sea.

Indonesia is believed to be reconsidering its decision to buy four Wing Loong UAVs from the Aviation Industry Corporation of China for its squadron in Pontianak, West Kalimantan, 460 kilometres southeast of Natuna Besar. Instead, it has been looking at Turkish Aerospace Industries’ Anka drones, which can remain in the air for up to 24 hours and have already proved themselves in surveillance and armed reconnaissance missions over Syria.

The Indonesian Navy has taken over most of the patrols in the North Natuna Sea since the rash of incidents in 2016, but analysts say it will take several years for Natuna Besar to evolve into a fully fledged base with the necessary fuel stockpiles to improve the range of effectiveness of navy operations.