In 1974 and 1975, a US ambassador battled Washington to support a negotiated solution to Cambodia's worsening conflict. Ambassador John Gunther Dean's document donation this April to the US National Archives paints a picture of failed diplomacy and holds lessons for today's statesmen. In this six-part series, VOA Khmer takes a detailed look at the final year of the Khmer Republic. LISTEN to KHMER audio versions of any story below. First click on headline, then click on the MP3 icon.