When Major-General Chen Xiaogong arrived in Washington to begin his assignment as China's military attache in the autumn of 2001, he thought he would be treated as a friend and with respect.
After all, the fluent English speaker knew the American capital well and was liked in Pentagon circles from his time as a visiting fellow at the US National Defence University and the influential Washington think-tank Atlantic Council in the late 1980s.
But when General Chen completed his two-year stint recently and returned to Beijing to become the PLA's representative to the Ministry of Foreign Affairs' newly established National Security Bureau, he was far from happy.
The reason? US Secretary of Defence Donald Rumsfeld had ordered a halt to all contact with the Chinese military in the aftermath of the Hainan island spy plane incident in April 2001.
For more than a year, sources said, Mr Rumsfeld and his deputies had rejected General Chen's numerous requests to visit the Pentagon and meet US officers.
Mr Rumsfeld even denied him the diplomatic protocol of presenting his credentials. Like ambassadors, the senior military attache is normally granted a ceremonial meeting with the host nation's secretary or minister of defence.