China’s South China Sea claims have no legal foundation - US ambassador

Metro Manila, Philippines - US Ambassador to the Philippines MaryKay Carlson reaffirmed her country’s strong support for the 2016 Arbitral Award and asserted that China’s expansive claims in the South China Sea have no basis under international law.

Speaking at a forum organized by the Stratbase ADR Institute in Makati City to mark the ninth anniversary of the landmark ruling, Carlson said the decision of the Arbitral Tribunal at The Hague, Netherlands was a clear victory for international maritime law and regional stability as well.

“The 2016 ruling clarified critical truths: that China’s so-called ‘nine-dash line’ and any claims to ‘historic rights’ have no legal foundation,” Carlson said. “The decision remains final and legally binding on the Philippines and China.”

Carlson said the ruling invalidated any attempt by China to use its sweeping maritime claims to deny the Philippines its sovereign rights over its exclusive economic zone and continental shelf. She warned that Beijing’s continued defiance of the ruling and its unlawful activities in the West Philippine Sea threaten peace, security, and freedom of navigation across the Indo-Pacific.

“Beijing has ignored the ruling and continues to operate with impunity…China continues to assert territorial sovereignty and exclusive rights where none exist under international law,” she said.

She described China’s activities in the region as illegal, coercive, aggressive, and deceptive, including dangerous maneuvers, environmental degradation, and harassment of lawful maritime operations not only by the Philippines but also by other Southeast Asian states such as Vietnam, Malaysia, Brunei, and Indonesia.

The US envoy reaffirmed Washington’s “ironclad” commitment to its alliance with the Philippines, saying the Mutual Defense Treaty between the two countries extends to any armed attack on Philippine military or Coast Guard assets anywhere in the South China Sea.

“The United States and the Philippines stand shoulder-to-shoulder as ironclad allies, bound by shared history, common values, and an unwavering commitment to a free and open Indo-Pacific,” Carlson said.

“Our commitment is unwavering, rooted in our 1951 Mutual Defense Treaty,” she added.

Carlson also expressed support for President Ferdinand Marcos Jr.’s renewed efforts to assert the Philippines’ maritime rights through transparency and strategic engagement. She said the United States is proud to support the Philippines through joint military exercises, infrastructure cooperation under the Enhanced Defense Cooperation Agreement, and maritime domain awareness programs.

She noted that the alliance is backed by a growing network of regional and global partners, including Australia, Japan, India, the United Kingdom, Germany, France, South Korea, and ASEAN claimant states, who collectively support a rules-based international order.

“Together, we send a clear message: coercive actions have no place in international law,” she said. “Let us ensure that the South China Sea remains a sea not of conflict but of opportunity - of peace and prosperity for all.”