It is ``probably the end of an era in terms of Soviet intelligence gathering in the US,'' the senior Reagan administration official said with a grin. On Tuesday the United States expelled 55 Soviet diplomats, the largest mass expulsion in US history. The result, the beaming official said, was to ``decapitate'' the Soviet intelligence effort in America.
So expansive was the administration's mood over the beheading that three senior men in sensitive positions, men usually tight-lipped about their work, talked to a few reporters, on condition that they be identified only as ``administration officials.''
According to them, Moscow has been dealt a body blow from which it will take years to recover.
For among the Soviets now packing their bags for a Nov. 1 departure, they said, was virtually the entire remaining leadership of the Soviet intelligence-gathering effort in the US.
Other spies had already left, having been expelled from the Soviet UN mission last month.
According to the administration, among the departed and departing ``diplomats'' were the New York and San Francisco rezidents, station chiefs, of the KGB, the Soviet secret service, as well as the chiefs of virtually every ``line'' (department) working under them. The GRU, the Soviet military intelligence arm, was similarly savaged.
``They were the avant-garde, the best and the brightest,'' a US official said.
But he estimated that from 75 to 100 other agents remained in place among the 250 Soviet diplomats still accredited in the US.
Smoking them out, administration officials made clear, would still present a challenge. ``You've got to remember,'' one said, ``that they don't exactly present calling cards identifying themselves.''
For years, according to the officials, the US has been something of a training ground for the KGB and the GRU.
One official said the Soviet diplomatic community in the US, numbering up to 320, was so heavily salted with GRU and KGB agents -- many returning for their second and third tours -- that first-tour agents were able to do ``everything up to prosecutable espionage,'' freeing their superiors to oversee their work and also concentrate on major operations, such as assembling spy rings, recruiting vulnerable Americans in sensitive positions, or stealing high-technology secrets.
According to the administration, Lev Zaitsev, identified as a Soviet consular employee in San Francisco, in fact was the KGB rezident overseeing Soviet intelligence efforts targeted on Silicon Valley.
The chief of ``Line X,'' scientific espionage, and his deputies in New York and Washington are also among the expelled, according to the administration. So is the chief and his deputies in ``Line KR,'' responsible for counterintelligence, along with the chief of ``Subline K,'' which keeps watch over Soviet diplomats in the US and keeps them from straying from the fold.
The agents left behind, says one official, are mainly involved in ``sigint'' (signals intelligence, or electronic eavesdropping), administrative tasks, and other low-prestige work.
``There is,'' says one official, ``no management left.''
According to US officials, the expulsions will have ramifications for years to come. They will probably force the KGB and GRU to promote lower-level agents already in place to take over the reins. The new men, presumably with less experience, might be more prone to mistakes.
The expelled Soviets, one official said, are some of the best the KGB and GRU could produce. Their fluency in the language and skills in espionage tradecraft had been honed through years of training and experience, at a considerable investment of time and money.
Now, they are branded, unable to work in the West because of longstanding agreements between NATO allies and other countries that none will accept Soviet diplomats expelled from another country on charges of spying. Last year, 41 Soviets were expelled from Britain for espionage, further limiting the numbers of agents who can work in the West.
Administration officials acknowledged that Moscow might try to infiltrate more illegals, agents working without diplomatic cover, into the US to make up for its losses. But it will take several years to establish a legend for them, says one official, referring to the string of false papers and work experiences that provide plausible cover. Moreover, says another, illegals lack the sophisticated equipment that allows them to communicate with Moscow without increasing the risk they will be uncovered.
One likelihood, according to administration experts, is that more traveling Americans will be targeted outside the US, in an effort to persuade, or compel, them to collaborate with the Soviet Union. And more third-country nationals, such as Latin American diplomats, will probably be recruited.
But they indicate these risks pale in comparison with the damage done to Moscow by the mass expulsions.
``We're not going to make it [espionage] go away,'' one official says, ``but we'll certainly make it a lot harder.''