Lee spent a good portion of his life battling against the GATT (later World Trade Organization). According to him, this organization killed South Korean farmers and fishermen. In 1993, he attempted suicide at the GATT's Geneva, Switzerland, offices, but was hospitalized and recovered.
On September 10, 2003, Lee showed up at demonstrations near the WTO's convention in Cancún, Mexico, and stabbed himself in front of the television cameras, giving what was supposed to be a peaceful demonstration a tragic ending. Although he was rushed to a local hospital, he died during surgery.