Asia Defense | Security | East Asia

The Iran-Israel-US War Is Reconfiguring US Force Posture in the Indo-Pacific

The concentration of U.S. military assets in the Middle East is forcing allies like Japan and South Korea to ask themselves hard questions about U.S. reliability.

Arleigh Burke-class guided-missile destroyer USS Delbert D. Black (DDG 119) fires a Tomahawk Land Attack Missile (TLAM) in support of Operation Epic Fury, Feb. 28, 2026.

Even before the outbreak of war in the Middle East, South Korea was wary of U.S. calls for “strategic flexibility” or the potential use of U.S. Forces Korea (USFK) to counter China. Now that the United States is reallocating air defense assets from the Korean Peninsula to the Middle East, those concerns have taken on a new urgency. While South Korean President Lee Jae-myung opposed the U.S. decision, he also stated that he could not “impose [South Korea’s] position” on the United States. 

U.S. defense officials have downplayed Asian allies’ concerns about a decreasing stockpile of munitions – including missiles – and the concentration of U.S. military assets in the Middle East. While some administration officials – such as Elbridge Colby – might say that the United States is “laser-focused on the First Island Chain” of Japan, the Philippines, and Taiwan, and focused on “very close alignment with [U.S.] allies and partners in the region,” words are cheap. Moving multiple Terminal High Altitude Area Defense (THAAD) system launchers out of bases in South Korea and one-third of the U.S. naval surface fleet to the Middle East sends a very different message.

The USFK’s Patriot missile defense system, guided bomb kits, and the MGM-140 Army Tactical Missile System have been redeployed. It is unlikely that the THAAD radar has been redeployed, but some THAAD launchers and missile interceptors may have been.

South Korea can partially replace the Patriot system with its own air defense assets – the Cheongung-II system. South Korea also plans to deploy a long-range surface-to-air missile system, L-SAM, and the SM-3 interceptors aboard Aegis destroyers, in the early 2030s. But in the meantime, there is no domestic alternative for THAAD to intercept missiles at altitudes above approximately 100 km. 

Lee insists South Korea’s deterrence will not be weakened, though analysts are divided over government claims. It likely depends on which elements of THAAD are being redeployed and for how long. The last question, in particular, is unanswerable. 

Beyond the immediate concern about military deterrence vis-à-vis North Korea, there is also the concern about diplomatic relations with China. Given the political turmoil in China-South Korea relations caused by the initial deployment of THAAD to South Korea in 2017, it may be not only physically challenging but also politically challenging to return THAAD to South Korea when the United States wants to. China’s opposition to THAAD in South Korea has remained........

© The Diplomat