Philippine domestic divisions and public “word wars” with China risk undermining Manila’s credibility as 2026 ASEAN Chair and eroding ASEAN centrality at a critical moment. Effective leadership will require projecting internal coherence, rallying broader ASEAN unity among claimant and non-claimant states, and converting the Code of Conduct pledge into concrete, legally grounded diplomatic progress.
As the Philippines assumes the ASEAN Chairmanship in 2026, Manila has pledged “to endeavour to conclude the negotiation of an effective and substantive Code of Conduct (COC) that is in accordance with international law, particularly the 1982 United Nations Convention on the Law of the Sea (UNCLOS), within 2026.” This commitment places the Philippines at the centre of one of Southeast Asia’s most consequential diplomatic tests: whether ASEAN can finally translate decades of aspiration into a binding framework for managing disputes in the South China Sea. Because the ASEAN Chair sets agendas, shapes negotiating pace, and mobilises political momentum, the Philippines’ ability to project internal coherence and regional leadership will determine whether ASEAN centrality is strengthened or further eroded.
Yet domestic political fragmentation and persistent regional disunity threaten to undermine the credibility required for effective leadership. Philippine President Ferdinand Marcos Jr. and Vice President Sara Duterte have adopted sharply divergent positions on China policy, publicly accusing one another of being either “pro-US” or “pro-China.” Vice President Duterte criticised plans for the deployment of US missiles in the Philippines, arguing that such moves would “antagonize China” and questioning the administration’s claim to an independent foreign policy. In response, the Marcos administration asserted that while the Dutertes may be “pro-China,” the president is “pro-Philippines.” For ASEAN partners and China alike, such visible divisions raise doubts about the durability of Philippine commitments. When foreign policy appears vulnerable to domestic political shifts, negotiating partners have fewer incentives to compromise, while external powers gain opportunities to exploit internal fissures or simply wait out political uncertainty.
These divisions have spilled into the legislative arena. In an unusually public escalation, the Chinese embassy in Manila issued a series of confrontational social media statements attacking Philippine officials and disputing claims regarding China’s actions in the West Philippine Sea. Philippine lawmakers responded in kind. A draft Senate resolution condemning Chinese actions garnered strong support from the majority bloc but little backing from the minority, many of whom are aligned with the Duterte camp. This public “word war” transformed what could have remained a manageable diplomatic dispute into a high-visibility confrontation, generating audience costs on all sides. As rhetoric hardens, negotiators lose room for manoeuvre, rendering technical compromise within the COC process increasingly difficult.
The political fallout quickly reverberated through diplomatic channels. Senate Foreign Relations Committee Chair Erwin Tulfo warned that the escalating exchanges could delay COC negotiations, while the Philippine Department of Foreign Affairs urged lawmakers to tone down personal attacks to preserve ongoing dialogue with Beijing. These developments invite a crucial question: what message is the Philippine government sending to its ASEAN neighbours? To many member states, inconsistency signals that Manila may struggle to convert chairmanship authority into concrete outcomes. This perception reinforces hedging behaviour, as partners hesitate to commit amid uncertainty over Philippine follow-through. While claimant states such as Malaysia, Brunei, and Vietnam have also expressed urgency in concluding the COC, the elusive conclusion of the Single Draft Negotiating Text (SDNT) after two decades of talks underscores how damaging further delays would be—especially if they stem from the Chair’s domestic contradictions.
Domestic Political Fragmentation and the Credibility of ASEAN Leadership
The Philippines’ internal political crises—ranging from executive–legislative infighting to impeachment complaints and deep divisions over China and US policy—have produced inconsistent foreign policy messaging. This undermines confidence among ASEAN partners and complicates Manila’s ability to steer sensitive negotiations such as the South China Sea COC. ASEAN members and China will judge the Philippines not only by its legal arguments, but by whether it can speak with one voice. In diplomacy, credibility derives less from neutrality than from consistency, predictability, and the demonstrated capacity to implement commitments.
To meet this challenge, the Marcos administration must adopt a genuine whole-of-government approach to ASEAN chairmanship. Foreign policy positions should be aligned across all branches of government and anchored firmly in sovereignty, national interest, UNCLOS, and the 2016 Arbitral Award. Such coordination would reduce the risk of inadvertent escalation, strengthen the Chair’s authority at the negotiating table, and reassure partners that Philippine commitments will remain stable across political cycles. Equally important, Manila must redirect contentious exchanges with China away from social media and public confrontation toward institutionalised diplomatic channels. Defending legal rights need not—and should not—come at the cost of narrowing the political space necessary for compromise within the COC framework.
ASEAN Unity and the Limits of Consensus
The Philippine case also reflects a broader structural challenge confronting ASEAN. The association’s muted response to the 2016 arbitral ruling and the prolonged deadlock over the SDNT reveals how hedging behaviour—often framed as “non-alignment”—has weakened ASEAN unity and diluted the effectiveness of consensus-based decision-making. This fragmentation undermines ASEAN’s ability to uphold its core norms: peaceful dispute settlement, renunciation of force, freedom of navigation, and respect for territorial integrity, as enshrined in UNCLOS and the 2002 Declaration on the Conduct of Parties (DOC). In practice, disunity lowers the diplomatic cost of delay for Beijing and facilitates divide-and-rule strategies that privilege bilateral engagement over multilateral constraint.
While the coherence of the Chair is vital, responsibility for progress cannot rest on Manila alone. Influential non-claimant states such as Indonesia and Singapore can reinforce legal principles without appearing confrontational, while claimant states like Vietnam and Malaysia can help maintain negotiating discipline by coordinating technical positions. Shared leadership reduces the risk that ASEAN’s collective agenda becomes hostage to any single member’s domestic politics.
Frequent and institutionalised high-level ASEAN–China exchanges are also essential. Regular engagement reassures both sides of their commitment to concluding the COC, reduces misperceptions, and raises the political cost of abrupt policy reversals. Beyond this, claimant states within ASEAN—Malaysia, Vietnam, Brunei, and the Philippines—should function as a caucus to project urgency and coherence. Pre-summit coordination on minimum common denominators can help resolve contentious issues such as geographic scope, the legal relationship between the COC and the DOC, and operational definitions of key terms like “disputed feature,” “incident,” and “self-restraint.” These are not semantic disputes; they define the scope of obligations, compliance expectations, and crisis behaviour. Convergence among claimants would shift negotiations from intra-ASEAN disagreement to genuine ASEAN–China bargaining, significantly enhancing collective leverage.
The Philippines’ challenge as ASEAN Chair is therefore twofold: restoring domestic credibility and strengthening regional unity. Addressing only one without the other will be insufficient. If Manila succeeds in aligning its internal political signals while mobilising ASEAN toward coordinated action, it can help deliver a substantive, legally grounded Code of Conduct that reinforces regional order. Failure, however, would further hollow out the COC process and deepen perceptions of ASEAN’s declining relevance in regional security. Even incremental progress would demonstrate that Southeast Asian middle powers, acting collectively, retain the capacity to shape outcomes through law, diplomacy, and institutional resilience.
This piece was originally written for the Counterpoint Southeast Asia series, published by the Centre on Asia and Globalisation. It received 2nd prize in the Counterpoint Southeast Asia Student Competition organised by the Centre on Asia and Globalisation (CAG).