The littoral nations of the South China Sea appear to be closing ranks against China’s territorial claims to 90 percent of the sea. With China pressing its approach through its nine-dash line on its maps and passports, there is no sign Beijing will relent on a territorial vision many find outrageous.

In this atmosphere, the visit of US President Barack Obama in the past week has focused attention on strengthening US security links with both Malaysia and the Philippines. Less noticed, yet at least as important for the long run, was last month’s statement from Jakarta, subsequently reinforced by armed forces chief General Moeldoko, that Indonesia is also now in direct conflict with China over the nine-dash line.

“Indonesia is dismayed,” Moeldoko wrote in an opinion piece in the Wall Street Journal on April 24, “that China has included parts of the Natuna Islands within the nine-dash line, thus apparently claiming a segment of Indonesia's Riau Islands province as its territory.”

Overall, Obama’s trip to Asia was a mixed bag and did not convince all of the seriousness of the US “tilt” to the region that began in 2012. Japan remains as self-destructively adamant about protecting its farm lobby as about visiting the Yasakuni shrine, offering the US basically nothing in return for Washington’s commitment to its defense, including over the Senkaku/Diaoyu islands dispute with China.

Obama’s South Korea trip was overshadowed by the ferry sinking disaster, a tragedy of national proportions for the Koreans.

But it was a different story in Southeast Asia. In the Philippines, only a few voices are now heard opposing the return of US military forces ‑ albeit technically on a temporary basis ‑ to Philippine defense facilities, 22 years after Manila rejected a bitterly negotiated bases treaty with Washington. The difference is, of course, China. And although the US remains technically neutral on island claims issues, it is now underwriting the upgrading of the Philippines grossly inadequate naval and air capability and the new pact over facilities will give a morale boost to those who say that territorial integrity must take precedence over the possible economic cost of facing down the Chinese. The US is also helping assemble evidence to bolster the Philippine case against China being brought to the International Court in The Hague, a move that has also angered Beijing.

Perhaps more surprising, if less concrete, was Obama’s visit to Malaysia. The US clearly put aside its concerns over human rights issues ‑ especially the persecution in the courts of opposition leader Anwar Ibrahim, the rigging of the electoral system and ethnic and religious discrimination – to focus on “deepening” the relationship with Malaysia, a strategic goal linked to the US promotion of the Trans-Pacific Partnership (TPP) trade deal but not unrelated to China’s territorial drive.

Malaysia has long had much closer defense ties with the US than it publicly admits but it has also kept quiet about China’s aggressive actions, first towards Vietnam and more recently the Philippines in the South China Sea. It preferred not to offend China, perhaps fearing Beijing’s intervention in its domestic affairs on behalf of the ethnic Chinese minority, even though in the long run it is as exposed to enforcement of the nine-dash line as Vietnam and the Philippines.

Prime Minister Najib Tun Razak seems to have decided that more overt ties with the US are now in order. Malaysia may finally be genuinely disturbed by Chinese actions against the Philippines and perhaps also agitated by China’s response to the disappearance of Malaysia Airlines flight MH370, which has shown Beijing making claims that smack of regional hegemonism and ethnic chauvinism.

The Obama visit and the MH370 saga both overshadowed the March 12 announcement from Jakarta that China’s nine-dash line covered an area including some of the Natuna Islands off the northwest coast of Borneo that are part of Riau province. Indonesia had long sought but failed to receive clarification on the coordinates of China’s claims and it had tried to present itself as a mediator on the grounds that it was not directly involved in the disputes over the sea.

This stance, promoted by the foreign ministry, was partly to boost the country’s role in an Association of Southeast Asian Nations divided between those in dispute with China over the sea and those ‑ like Cambodia, Laos and Myanmar ‑ with no such conflict. The division has sparked considerable bitterness in recent years. Jakarta has also hoped that China could be persuaded to abide by the 2002 Declaration on the Conduct of Parties in the South China Sea not to use force to implement claims or otherwise upset the status quo.

But clearly Indonesia has concluded that China is not listening but simply building up its naval capability, meanwhile pressing claims such as the Scarborough Shoal dispute with the Philippines whenever an occasion arises. In March 2013, after an Indonesian patrol boat arrested a Chinese vessel fishing in waters off the Natuna Islands, a more heavily armed Chinese ship forced the Indonesians to release the fishing boat and crew. Indonesia kept quiet about this as Foreign Minister Marty Natalegawa seemed under the illusion that somehow neutrality and diplomacy would ward off the Chinese.

However, China’s many actions since then – including a ban on fishing that appears to cover more than half the South China Sea and attempts to thwart Philippine re-supply of its Second Thomas Shoal garrison – has caused a strategic reassessment by Jakarta. China appears for all practical purposes to reject the United Nations Convention on Law of the Sea (UNCLOS), which provides not only for 200-mile Exclusive Economic Zones ‑ which put the Scarborough Shoal, James Shoal, Mischief Reef and other features occupied or claimed by China clearly in the hands of the Philippines – but also created the concept of an archipelagic state, which treats waters connecting islands that are part of an archipelago as internal waters. As the world’s largest archipelagic state (followed by the Philippines) this principle is of huge strategic importance to Indonesia.

So the lead role for Indonesia on South China Sea issues now appears to have moved from the foreign ministry’s ethereal world of make-believe diplomat-speak to General Moeldoko explicitly stating that China’s claims include Indonesian territory. “The Indonesian military has decided to strengthen its forces on Natuna,” Moeldoko wrote. “We will need also to prepare fighter planes to meet any eventuality stemming from heightened tensions on one of the world's key waterways.”

While the general is careful to say Indonesia seeks a peaceful solution and hopes that neither China nor the US ups the ante to the point of confrontation, Jakarta’s stance represents a new chapter in the willingness of Indonesia, Malaysia and the Philippines to resist Chinese expansionism.