MediumIII Kinetic Conflicts & Defence23 October 2026, Friday
Teodoro says force against Sierra Madre would be an act of war
Philippine Defence Secretary Gilberto Teodoro said on 23 October that any use of force against BRP Sierra Madre, grounded on Ayungin Shoal since 1999, would be treated as an act of war. He was responding to an unconfirmed newspaper report that Beijing was weighing 10 countermeasures.
According to Philstar, the Chinese Commercial News, a Chinese-language paper published in Manila and seen as close to Beijing, wrote on 22 October that China was considering 10 options in response to Manila's recent moves. The list includes towing the ship away, cutting off crew resupply, sanctioning politicians seen as anti-China and curbing fuel and fertiliser shipments. The paper itself noted that the measures had not been confirmed by Chinese authorities. It also said it was unclear whether they had entered any formal decision process.
Teodoro distinguished an 'act of war' from a 'state of war'. Under the 1987 Constitution, only Congress can declare a state of war, by a two-thirds vote of both chambers voting separately. He said the 1951 Mutual Defense Treaty could come into play in such an incident, but that the decision rests with President Marcos. The Inquirer reports that Teodoro also called for amending the law that caps military modernisation spending at 50 billion pesos.
The resupply dispute also remains open. Through state media outlet Global Times, the China Coast Guard claimed the 21 October resupply was carried out with Chinese approval and that it inspected the Philippine vessel. Teodoro denied this. Rear Admiral Roy Vincent Trinidad, the Philippine military's West Philippine Sea spokesman, confirmed on 22 October that no permission had been sought. The foreign ministry summoned Ambassador Jing Quan, who had said China could easily win a conflict. Philstar dates those remarks to 19 October, the Inquirer to 15 October.
Talay assessment
Bottom line
Teodoro's distinction ties Manila's deterrence to physical interference with the Sierra Madre. Grey-zone steps such as blocking resupply or economic pressure stay below that threshold. Because the 10 measures rest on a single unconfirmed newspaper, the most likely path is that the 2024 arrangement holds while the resupply dispute hardens. The real risk is not towing the ship but a quiet squeeze on economic channels such as fuel and fertiliser.
Likely effects
- South China Sea securityNegativeWeeks
The claim that resupply missions need Chinese approval turns every rotation into a political test; the 21 October dispute raises the risk of contact on the next run.
- US alliance commitmentUncertain1–6 months
By invoking the 1951 treaty, Teodoro confronts Washington with the question of becoming a direct party if force is used against the Sierra Madre.
- Philippine economyNegative1–6 months
The list includes curbs on fuel and fertiliser shipments; if that channel is used, farm input costs and inflation build domestic pressure on the government.
Possibilities, ranked
- 1War of words, arrangement holds60%
Beijing does not formalise the measures and resupply continues under the 2024 arrangement, but every rotation turns into a battle of statements.
Watch: The next Ayungin resupply and whether the China Coast Guard repeats its approval claim
- 2Selective economic pressure30%
China applies one of the economic measures on the list, such as entry bans on politicians or trade curbs, without touching the ship.
Watch: A sanctions announcement against Philippine figures by China's foreign or commerce ministry
- 3Resupply actually blocked10%
The China Coast Guard stops or turns back a resupply boat and Manila formally raises the treaty question.
Watch: A Philippine military statement that a resupply mission was blocked
Probabilities are calibrated judgement based on the sources, not measurement, and are revised as new information arrives. Not investment advice.
Market reaction
Indicators affected
- Unconfirmed countermeasures▼ 10
- Modernisation cap▼ 50bn pesos
- Sierra Madre grounded▲ 1999