THE revelation that Aldrich Ames, a United States CIA official, had spied for the former Soviet Union and Russia since 1985 is a damaging blow to American security - and an insight into American naivete. If the apparent crimes of Ames and his wife Maria are proven, this will amount to one of the worst cases of treason in United States history. A stream of secrets was sold to Moscow over nine years and for a pretty penny - almost HK$12 million. Included in the information may have been the names of Russians co-operating with the US - a tip-off that seems to have led to a number of executions. Yet there is something other than anger in the US reaction to the disclosures. It is more akin to outraged innocence, as though senior officials are surprised and hurt that Russia would continue spying on the US after the end of the Cold War, when the two countries stopped being ''enemies''. It may be unwise for Russia to be engaged in espionage against the US while it is asking for American aid to help it beat some of its economic problems. But it should not be surprising. As the revelations this week about Australian security officers spying in Hong Kong would seem to confirm, most countries spy on other countries. As the Australian disclosures also suggest, much modern espionage is commercial and industrial. But nations still engage in political and military espionage. The Russians might have kept on spying on the US after the Cold War ended because both countries retained military machines that were geared to fight each other. But the continued espionage is not a result mere inertia: the US has commercial, industrial, diplomatic, technical and military secrets about which its old rival would be desperate to learn. The real test of whether America should be surprised lies closer to home: did the CIA stop spying on Russia after the Soviet Union collapsed? The answer is certainly not, which is why the Russians could comfortably pretend that they would have stopped spying on the US if the US had stopped snooping on them. Similarly, America's real problem is internal. The affair has exposed a massive breach of its intelligence operations. A CIA officer and his wife were able to supply secrets to another nation, and indulge themselves with their illicit earnings in an expensive lifestyle well beyond the means of government employees. And they were able to do both for years before finally being caught. A glance at the record shows that the security of the CIA has been compromised so often that this is almost routine. Protesting to the Russians will do little good, other than to make American leaders feel better. They will stop, or limit, the spying onlywhen they attend to their own service and its security.