The writer was the FBI's chief analyst for Chinese intelligence for more than 20 years.

One of the problems the FBI and other U.S. counterintelligence agencies have long had with attempting to neutralize Chinese intelligence-collection operations in the United States is that the people who covertly gather intelligence for China normally don't look like spies, act like spies or pilfer large amounts of secret information. Curiously, it is this exact aspect of Chinese intelligence practice that is driving the recent spate of arrests and convictions of U.S. researchers in China.

For most areas of Chinese intelligence collection, the actual work of locating and obtaining desired information, even very sensitive data, is carried out by academics, students, businessmen or journalists. Chinese intelligence officers typically do not direct or control the effort, because it is Chinese intelligence consumers who determine the nature and extent of Chinese collection operations, just as it is U.S. consumers whose purchases shape the U.S. economy.

Since they are not intelligence professionals, Chinese collectors do not understand or make use of clandestine techniques such as "dead drops" under pedestrian bridges in parks; instead they tend to rely on simply sitting down with a knowledgeable friend or contact and asking confidentially for information or assistance. The normal consumer collects information for his own use or for his immediate co-workers, so his collection goals are very modest. Even when a collector pilfers sensitive or classified information, it is normally in small pieces.

U.S. counterintelligence has a great deal of trouble with China's consumer-driven approach to intelligence collection because U.S. defenses were built with the idea of stopping the Soviets, whose operations typically are run by intelligence officers who look like intelligence officers, act like intelligence officers and are ambitious collectors of a large volume of high-quality U.S. secrets.

Chinese counterintelligence has encountered the same problem as the United States, but in a different form. While the United States anticipates that its espionage adversaries will act the way the Soviets did in their heyday, Chinese counterintelligence assumes that China's adversaries will collect inside China just the way China collects abroad.

There are too many visitors to China to investigate everyone, so it seems to me that China has been searching out individuals with a Taiwan connection of some sort and putting them under much closer scrutiny than others. This would be a natural thing to do, because people with close Taiwan ties are considered to have a built-in motive for spying against the People's Republic of China.

In Chinese counterintelligence eyes, the professors, graduate students, journalists and businessmen who arrive in China in ever-increasing numbers for activities other than tourism look like natural spies. When subjected to counterintelligence scrutiny, their normal professional relationships with colleagues and friends as they go about the process of collecting information for research projects or news stories can look sinister. Most telling, when they attempt to collect information from academic or professional journals to obtain data for their research projects, they can easily cross the line into what China considers "state secrets," because China has a much lower threshold for deciding what is classified, especially when the data find their way into foreigners' hands.

As far as China is concerned such visitors look like spies, act like spies and are collecting state secrets, probably for Taiwan. It seems clear to me that Chinese officials see their country being overrun by this phenomenon and have made a strong enough case about it to require that action with political consequences be undertaken. In this string of espionage arrests, security is driving politics, not vice versa.