Liao Ho-shu, interim chief of Communist China’s mission, persuading Dutch businessmen to invest in China, went to the Dutch police saying he wants to defect to the United States.

It was 4:30 on a cold January morning, no time for a self-respecting resident of The Hague to be on the streets, and the desk sergeant at police headquarters was baffled by the middle-aged Chinese, clad in pajamas and raincoat, who stood before him. From the mixture of broken Dutch…