MOU43 clarifies Thai–Cambodian border without redrawing it
The MOU43 aims to clarify existing borders under historical treaties, not to create new ones. It empowers the Joint Boundary Commission (JBC) to use modern technology in jointly surveying and marking boundaries with precision.
Deputy Director-General of the Department of Treaties and Legal Affairs, Songchai Chaipatiyut, clarified that the 2000 Memorandum of Understanding (MOU43) carries the full legal weight of a treaty, a formally ratified agreement aimed at clarifying the existing boundary between Thailand and Cambodia based on the 1904 and 1907 treaties between Siam and France, whose obligations Cambodia inherited.
He emphasised that the MOU does not create new boundaries but rather seeks to “define what already exists” with geographical precision.
Supporting evidence includes both historical treaties, maps drawn under those treaties, and related implementation documents. The MOU’s preamble explicitly states that “a clearly defined boundary will bring the greatest benefit to the peoples of both countries.”
Joint survey mechanism and modern technology
Lt Gen Chakorn Boonphakdee, Director-General of the Royal Thai Survey Department, noted that the Thai–Cambodian border stretches 798 kilometres, comprising:
- 524 km of watershed line,
- 216 km of river boundary, and
- 58 km of straight line.
Under the MOU framework, field operations began in 2006, divided into five phases, from locating 74 existing boundary pillars to using Light Detection and Ranging (LiDAR) technology for pinpointing precise watershed lines.
To date, more than 602 kilometres have been jointly surveyed, with 45 boundary pillars mutually agreed upon and 29 still pending.
The remaining 196 kilometres, where no markers ever existed, will be delineated using LiDAR to produce an accurate new joint map.
Once demarcation is completed, a final joint map and a “closing treaty” will be submitted to Parliament for ratification.
Map status: reaffirming Thailand’s rights
The 1:200,000-scale map from the French colonial era is considered too coarse for determining terrain boundaries.
Meanwhile, the 1:50,000-scale map produced by Thailand’s Royal Thai Survey Department serves internal security and development purposes but carries no international legal effect.
MOU43: a peaceful safeguard of sovereignty
The MOU established the Joint Boundary Commission (JBC) as a bilateral negotiation mechanism, with key provisions that:
- prohibit any alteration of the terrain during surveys, and
- allow diplomatic protests in cases of violations.
This framework serves as a legal and strategic safeguard of Thailand’s sovereignty. If the MOU were revoked, the entire negotiation process, including the 45 agreed boundary pillars, would be nullified, and Thailand would lose its advantage at the negotiating table.
Both agencies thus reaffirmed that the MOU43 is not a threat to sovereignty, but rather a mechanism of reason and science that keeps the border issue grounded in facts, not emotions.
