The Congressional Research Service of the U.S. said that “relations between South Korea and Japan are at lowest in decades, undermining the trilateral policy coordination with the U.S.” Experts at the Department of State say that if South Korea-Japan relations do not improve, the U.S. would focus on bilateral relations with Japan and QUAD (U.S., Japan, Australia, India) instead.
"Japan's relations with South Korea are perennially fraught due to sensitive historical issues from Japan's colonization of the Korean Peninsula from 1910 to 1945," Congress's think tank said on its report early this month. "Since 2018, these relations marked their lowest levels in decades," it added. "A series of actions and retaliatory countermeasures by both governments involving trade, security, and history-related controversies in 2018 and 2019 caused bilateral relations to plummet, eroding U.S.-South Korea-Japan policy coordination," the report said.
The reported described Japan as “key partner of the U.S., particularly in security and trade, with joint security objective ranging from responding to a growing challenges from China and threats from North Korea.” A high ranking official at the Biden administration commented that officials at the administration may give up expectations on South Korea if it continues to stay in the past and
does not look ahead.