China is taking over the South China Sea, and the US isn't doing enough to stop it, experts say

• China has ramped up its confrontations with the Philippines in the South China Sea in recent months.
• Despite having a defense treaty with the Philippines, the US hasn't come to its aid.

Tensions between the Philippines and China have heightened around contested waters in the South China Sea in recent months.

But despite Chinese behavior becoming ever more aggressive, the US hasn't come to its ally's aid.

"My guess is that there is certainly no desire on the part of the US to be involved in any clash with China," Collin Koh, a senior fellow at the Institute of Defence and Strategic Studies at Singapore's Nanyang Technological University, told BI.

In recent months China has engaged in increasingly aggressive operations against the Philippines around the disputed islands of Sabina Shoal, Escoda Shoal, and Second Thomas Shoal in the South China Sea.

In June, Chinese coast guards armed with swords and knives attacked Philippine vessels off the coast of Second Thomas Shoal, resulting in injuries and one soldier losing a thumb.

A month later, its largest coastguard vessel dropped anchor in the Philippines' exclusive economic zone off Escoda Shoal, which the Philippines deemed an act of "intimidation."

And as recently as last month, a spokesperson for the Philippine coast guard, Jay Tarriela, said China had deployed 40 vessels to block its delivery of supplies to soldiers stationed in Sabina Shoal.

Under its defense treaty, the US is supposed to come to the aid of the Philippines, its oldest treaty ally in Asia, if an armed attack occurs on its forces.

But it has so far failed to defend the Philippines in the contested waters.

Avoiding red lines

China has grown aggressive in its encounters with neighboring countries, ramming and sinking fishing boats, brandishing weapons, and firing water cannons, mostly via its coast guard.

Under the Mutual Defense Treaty, signed in 1951, the US must come to the Philippines' aid in the event of an "armed attack."

However, according to Timothy Heath, a RAND Corporation senior defense researcher, China is carefully avoiding triggering a US military response by "cleverly designing" operations that harm the Philippines "well below" the threshold of an armed attack.

China is exploiting "gray zone" operations by deploying mostly "non-military" assets like maritime law enforcement vessels and using "nonlethal" tactics, he told BI.

"Moreover, these incidents are occurring in disputed waters," he added.

According to a 2023 report by the Congressional Research Service, the US doesn't take a position on sovereignty over any of the geographic features in the South China Sea.

"Unless China uses armed force to attack Philippine forces or carries out aggressive actions in Philippine territory, there are limits to what sort of armed force the US is willing to employ against China," Heath added.

So far, China's security gamble appears to be working well, Koh said.

"China is comfortable with a long game, so long as it's able to mass maritime forces in the area," he said.

Time for a reset?

The US routinely deploys its Navy and Air Force to conduct surveillance and reconnaissance missions near the contested waters.

And last month, Adm. Samuel Paparo, head of the US Indo-Pacific Command, seemed to suggest that some limited support for the Philippines could be on the way.

Speaking at a conference, he said that the "escort of one vessel to the other is an entirely reasonable option within our Mutual Defense Treaty."

Alexander Lopez, a Philippine National Maritime Council spokesman, meanwhile, called for a review of the treaty, saying it needed to be adapted to new security challenges.

Since 1951, "the strategic landscape has changed so much," he said.

Heath, from RAND, suggested that this is perhaps an attempt by the Philippines to lower the threshold for US military involvement.

"But that could raise the risk of a US-China conflict, which is in nobody's interests," he said.

Another issue is that the defense treaty does not define what constitutes an "armed attack," according to a legal analysis by the US Indo-Pacific Command.

According to Koh, this is a "growing concern" for the Philippines because it leaves it "open to so much interpretation."

Countering China's expansion

Sari Arho Havrén, an associate fellow at the Royal United Services Institute specializing in China's foreign relations, said the US is already supporting the Philippines in various ways.

It frequently reaffirms its commitments, and helps the Philippines in efforts to modernize its military and deepen partnerships with countries pursuing similar security goals in the region, she said.

"The US support to the Philippines has remained robust," she added, "and it is one of the most vital US alliances."

However, the US' hands are being tied by ongoing conflicts in Ukraine and Israel, as well as fears over escalating tensions two months before the US presidential elections, Koh said.

"If there's going to be a clash, it will become fodder for either party, the Democrats and Republicans, who will capitalize on it to try to win the election," he told BI.

Against this backdrop, "China likely took the hint that the US isn't so committed because of distractions elsewhere," he said.

He added: "It appears that the Chinese calculations might have paid off."

According to Koh, because the US is seemingly unwilling to act now, the Philippines is unsure whether it will help and would rather de-escalate tensions with China.

However, long term, this could mean China effectively takes over areas of territory the Philippines claims.

Koh said China could hold the Philippines' future on the Second Thomas Shoal "hostage to the point that one day they'll be exhausted and have to leave."

"Ultimately," Koh said, China's "aim here is to demonstrate escalation dominance to the Filipinos but, of course, not just to the Filipinos but also to demonstrate to its allies like the US that they have an overwhelming numerical advantage there and that if there's going to be war, there will be costs."

For the US, those costs seem like ones it currently doesn't want to pay.