The research body under the South Korean National Assembly said on Thursday that the latest decision to deploy a U.S. missile system here could be subject to parliamentary approval, amid heated debate among the rivaling parties and the government over whether the security decision requires a legislative step.

A report from the National Assembly Research Institute, released at the request of Rep. Kim Hae-young of The Minjoo Party of Korea, said that the agreement between Seoul and Washington to station the Terminal High Altitude Area Defense system here can constitute an international treaty and require lawmakers’ approval.

In contrast to the government and ruling party’s position, the organization’s interpretation comes in support of the opposing lawmakers, mainly the third-largest People’s Party that has decided to pit itself against the deployment.

“The agreement could take the form of an arrangement to implement the already-approved bilateral treaties, but if the scope of (the THAAD agreement) goes beyond what was set forth in the treaties, an additional agreement should be created and ratified under the Constitution,” the report said.

The government has asserted that the THAAD agreement does not need parliamentary approval because the bilateral agreement is a part of an “implementation arrangement” under the ROK-U.S. Mutual Defense Treaty and Status of Forces Agreement.

Though the paper did not specifically assert that the controversial agreement should be put to parliamentary voting, much of the six-page report focuses on the hypothesis of it being viewed as a treaty, which would require such endorsement.

One of the rationales used by the paper was “the 1969 Vienna Convention,” an international law governing agreements between the states. Its article 31 provides that a treaty shall be “interpreted in good faith and in accordance with the ordinary meaning given to the terms of the treaty.”

Noting that the clause is intended to minimize infringement of the state’s sovereign right incurred by international treaties, the report said that the allies’ bilateral treaties should be treated in that context and could fail to govern some significant understandings in the THAAD agreement.

For instance, the report said it is “questionable” for the mutual defense treaty to allow the transfer of a new “weapon system” to Korea. The military transfer under Article 4 of the treaty, the report claimed, is only limited to the U.S. Army, Navy and Air Force and their military equipment, not a weapon system.

The report also pointed out that the SOFA agreement is insufficient to fully regulate the deployment of the U.S. missile system, saying that the bilateral agreement is only about the use of a Korean base to offer “logistical support” to the U.S. army stationed in Korea, not about introducing its missile system.

“International laws deem treaties as agreements which would incur the relationship between right and duties among states, regardless of their titles and formats. Thus, if an agreement incurs sovereign restriction and financial burden, it should take the form of a formal treaty,” the report said.

The report concluded that South Korea’s Constitution can view the THAAD agreement as an international treaty that requires parliamentary approval. The Constitution Article 60 provides that the Assembly has the right to ratify treaties that would incur grave financial burden on the state or people.

Lee Jang-hie, a professor emeritus at the law school at Hankuk University of Foreign Studies, agreed and said that the current bilateral treaties are not enough to address issues raised by the deployment of THAAD.

“The THAAD agreement requires the use of South Korea’s national property such as its artillery unit in Seongju, so it is beyond the scope of the SOFA agreement which governs the use of facilities from the U.S. forces stationed in Korea,” he said. 

But some experts refuted the argument. Lee Ki-beom, a research fellow at the Seoul-based Asan Institute for Policy Studies, said that the 1953 mutual defense agreement is broad enough to allow the deployment of the THAAD artillery.

“I think the 1953 agreement is more about dealing with conventional weapons. True, the specific wording would not deal with missile defense system such as THAAD. But I don’t think we should sign a new treaty every time we tries to adopt a new weapon system,” he said.

A Seoul-based law school professor, who requested anonymity due to sensitive issue, agreed, “I understand the parliamentary group’s concern, but in most countries, administrative branch exercises more authority in interpreting security-related agreement than parliamentary bodies.”

By Yeo Jun-suk (jasonyeo@heraldcorp.com)