The relationship between Tokyo and Seoul is in the news again ― and for all the wrong reasons. Last week, in an apparent sign of bilateral warming, a report from Korea’s Yonhap News Agency indicated that Japan and Korea were on the cusp of formalizing a longstanding commitment to share intelligence and security information on North Korea’s WMD programs.

The story claimed that government sources in Seoul were prepared to sign off on a General Security of Military Information Agreement (GSOMIA) with Japan. At the time the anonymous official noted that Korea’s intelligence network would improve under the deal and indicated that Japan “has a lot of intelligence on North Korea.”

Unfortunately, this important security pact seems ― at least temporarily ― to have been torpedoed by political posturing and misplaced national sentiment. The leaked news of the pact follows months of robust cooperation between Japan and South Korea on security issues which have historically lagged due to rifts over the legacy of Japan’s colonialism of the Korean Peninsula during World War II.

Earlier this month, Tokyo indicated that it would position ships with Aegis ballistic missile defence technology close to Korean waters in the Yellow Sea in order to more adequately detect and deter any further North Korean missile tests. Japan’s defence ministry faced intense scrutiny after it failed to quickly detect the North’s failed rocket launch this past April.

When the reports were leaked into the Korean media, a firestorm erupted and President Lee Myung-bak was accused of making backroom deals with a country still viewed under the light of colonization before and during World War II.

The sovereignty of Dokdo (or Takeshima to Japan), the naming of the Sea of Japan (or the East Sea to Korea) and the lack of resolution from Japan’s colonial legacy of World War II, all immediately became linked to Seoul’s proposed intelligence agreement with Tokyo. This is a story that has become familiar to watchers of Japan-Korea relations. The disagreements are considerable but not intractable.

Last year, the South Korean government indicated that it intends to construct a significant naval base on Ulleung Island in the East Sea (the Sea of Japan). The Ministry of Defence announced that it will team up with the Ministry of Land, Transport and Maritime Affairs to build the complex and establish a port in Ulleung capable not only of maritime defence but also of force projection. This reignited tensions between South Korea and Japan over their competing territorial claims to the Dokdo islets.

The row over the Dokdo islets has been a sticking point since the conclusion of World War II. South Korea has occupied the rocky atoll since 1954, and has consistently repudiated Tokyo’s claims to the territory. Both sides point to historical maps and treaties to prove the legitimacy of their claims. South Korea insists that Dokdo has been part of Korea since the 6th century AD, but that has been rejected by Japan, which points to maps from the 18th century AD showing the rocks as part of Japanese territory.

Compounding this seemingly intractable dispute is a conflict over the naming of the sea that surrounds Dokdo. Seoul refers to the sea between Japan and the Korean Peninsula as the East Sea, while Tokyo labels it the Sea of Japan.

Tensions over Dokdo have heightened again recently following Seoul’s announcement this past spring that it will see through a $1 billion commitment to secure the islets through investment in enhanced infrastructure, such as surveillance capabilities and helipads. The naval base on Ulleung Island is a significant part of this budget and is projected to cost about $300 million. When completed, the base will be capable of housing the country’s largest warships ― ironically part of the Dokdo class.

Japan has declined to officially respond to the new plan, but has maintained its stance that the islets are an integral part of its territory. Foreign Minister Koichiro Gemba has consistently vowed that Japan would not accept Seoul’s administration of the islands and would continue to take diplomatic measures to ensure the land is returned.

This proposal combined with the bungled GSOMIA is sure to further damage the relationship between Seoul and Tokyo. Relations between the two have lagged over the past few years as a result of chronic instability within Japan’s ruling party and an edgy South Korean government that has acquiesced to its military establishment as a result of bellicose actions from North Korea. Nationalist posturing over this dispute is not uncommon and both sides have routinely used the issue to divert attention from other issues or to gain domestic political favors.

Tokyo is struggling to chart an adequate policy to resolve the row, while South Korea also has a lot to lose from isolating Japan. Japan remains one of South Korea’s biggest trading partners, with more than $40 billion worth of goods and services exchanged annually.

Moreover, the two countries remain bound together ― politically and geographically ― against a truculent North Korea and its latent nuclear weapons program. Both sides must leave behind the domestic political gains associated with the historical rhetoric and consider the implications of a strategic divide.

By J. Berkshire Miller

J. Berkshire Miller is a security and defence analyst for the Diplomat, which is based in Tokyo. ― Ed.