All three giant pandas in the Washington zoo were set to begin a one-way trip back to China on Wednesday, leaving only a few of the cuddly creatures in the United States amid tense diplomatic relations with Beijing.The Chinese government tends to "bestow" pandas on "nations with whom China's relations are on the upswing, as a form of soft power projection," Kurt Tong, a former high-ranking US diplomat and managing partner of the Asia Group consultancy, told AFP. Relations between Washington and