US unpredictability drives Asian allies toward deeper mutual cooperation

September 4, 2026 at 05:20 PM1 min

This digest was compiled by AI from multiple sources — links to the originals are below.

South Korea and Japan are expanding cooperation on supply chains, energy, and advanced industries as US policy under President Donald Trump grows less predictable. The two governments signed a Supply Chain Partnership Arrangement in March and agreed in May to explore emergency energy cooperation. The rapprochement has continued under progressive South Korean President Lee Jae-myung and conservative Japanese Prime Minister Takaichi Sanae despite historical disputes.

Key Facts

South Korea and Japan signed a Supply Chain Partnership Arrangement in March 2026.
The Lee-Takaichi summit in May 2026 was their third meeting in seven months.
SK Hynix is considering a large memory-chip manufacturing investment in Japan.
President Lee Jae-myung highlighted cooperation with Japan in his August 15 Liberation Day address.

Drivers of Cooperation

China's growing power, North Korea's weapons programs, Russia's war in Ukraine, and supply chain disruptions were already pushing like-minded countries closer together. Trump's second term has added another incentive: the need for relationships that remain useful when US policy changes suddenly. The abrupt Pentagon order to reduce joint military exercises with South Korea caught Seoul off guard and underscored the uncertainty.

Seoul-Tokyo Rapprochement

The rapprochement begun under former South Korean President Yoon Suk-yeol and former Japanese Prime Minister Kishida Fumio has continued under Lee Jae-myung and Takaichi Sanae. In his August 15 Liberation Day address, Lee pointed to a year of shuttle diplomacy with Japan and highlighted cooperation in supply chains, energy, and advanced industries. The industry ministries of both countries established a regular policy dialogue covering trade, economic security, supply chains, and mineral resources. At the May summit, the two governments agreed to explore emergency cooperation involving crude oil and petroleum products while strengthening supply-chain resilience.