Thirty years ago, some 22,000 police, military, and administrative personnel flew to Cambodia for one of the U.N.’s largest peacekeeping missions. After decades of bloodied fighting between the Khmer Rouge communist rebels and government forces, the warring factions signed an accord for the U.N. to prepare the Southeast Asian nation for “free and fair” elections in a step towards democracy. Prime Minister Hun Sen, then 41, was in the middle of it all.