The Russian spy saga has been good, cheap entertainment.
It has presented us with the image of shady people living under assumed names while performing elaborate pantomime routines with luggage to get information that could surely be found more easily on the internet.
But there are good reasons to examine this more closely; and not just because it should make us wonder about our secrets and their safety. In fact, it can be argued that espionage is good for security, even espionage by our enemies: perhaps especially by our enemies, if it helps them understand us a little better and makes them feel more secure.
Most world powers tacitly accept this trade-off: they spy on us, and we spy on them, and the world is a safer place as a result. Most people accept that their own governments are entitled to spy on others, just in case they are hostile or lying; is it really anything but hypocrisy to expect the others to behave differently?
Forget the idea that Google has eliminated the need for intelligence. Much information, it is true, is more freely available than ever before.
But the hard stuff – the critical and sensitive details of national security planning, like the intention to go to war – is not; and nor is the really soft stuff, the thoughts and feelings of others.
The justification for intelligence-gathering is that there is still information that either is so secret that it can only be gathered by covert means, or is inside someone's head. You won't find the president pondering his plans on Facebook. And that is the critical element: human intentions can only be judged by humans.
Huge advances in technical intelligence, signals and surveillance have boosted the capacity of governments to make assessments about the capabilities of their enemies – their location, armaments, disposition, equipment – but their intentions remain opaque, as decision-makers have discovered only too often.
Judging those is the job of the most highly-placed intelligence agents – agents that would be serviced by intelligence officers like the deep-cover illegals uncovered last week by the US. They weren't there to spy on their suburban neighbours over the hydrangeas; they were there because they could meet the most sensitive sources without causing any concern to anyone.
Both sides, in the Cold War, knew the value of espionage; and they would even, on occasion, acknowledge that there was a balance that helped preserve the peace. In 1987, when the US discovered that Moscow was bugging its embassy (shocking!), Secretary of State George Shultz admonished Russian President Mikhail Gorbachev for a breach of trust. Mr Gorbachev told him not to be naïve: indeed, he said, spying was a critical means of promoting stability.
Jack Matlock, former US ambassador to Moscow, tacitly admits in his memoirs that Mr Gorbachev had a point. "Espionage, after all, is one means by which governments verify that agreements are kept," he said – a crucial check on the other side, which both know is there and which keeps them (kind of) honest.
The best case for the importance of spies comes from the early 1980s, when the Cold War was threatening to turn white-hot. Ronald Reagan's rhetoric and the increasingly forward strategies of his military alarmed the Russians and convinced them that war might be edging closer; more importantly, that it might come without warning.
Yuri Andropov, the crumbling gerontocrat in charge of the Kremlin, nursed a particularly bad case of Cold War paranoia. According to Oleg Gordievsky in his book, Comrade Kryuchkov's Instructions, Moscow launched an operation to improve intelligence – Operation Ryan, Raketno-YadernoeNapadenie ("Nuclear Missile Attack").
Ten months later, the West began feeding their most paranoid fantasies with Able Archer, a nuclear command post exercise. It involved no real weapons, but it clearly looked awfully real to the Russians. Moscow Centre, alarmed, sent residencies a flash telegram reporting an alert on American bases and asking for further information. The message was clear: the Russians were thinking of hitting America first, before the Americans launched. How did the spies help? They seem to have played at least a small role in calming Moscow and reassuring it that the exercise was just that: an exercise.
But more important, the West also had its spies. The US initially refused to countenance that Russia had ever believed that war was imminent, but the evidence from its own intelligence sources convinced them otherwise: this had nearly sparked the Third World War.
The Soviet Union in 1987 was a closed, authoritarian state that feared for its place in the world, and it couldn't read its adversary well. Espionage probably helped persuade its leadership that they had less to fear than they had thought. We in the West would have been better off, in fact, if the Russians had known more: if their spies had been closer to the centre of power and more able to reassure their leaders.
Russia was often well-served by its intelligence machine, as Vladimir Putin well knows. Its intelligence officers were among the most clear-sighted members of the ancien régime and they saw long before others which way things were heading. And most importantly, its leaders trusted them, when they didn't trust either the reassurances of Western diplomacy or publicly available information which they regarded as propaganda.
Of course, there is just as much – perhaps more – bad intelligence as good: but Iraq, the Falklands, or Pearl Harbour all show the dangers of failure to collect intelligence, or its abuse, not of spying itself. By creating greater transparency – giving states greater insights into their adversaries and their intentions – espionage can contribute to making the world a safer place.
And if it helps persuade our adversaries that our intentions are peaceful, it seems a small price to pay – to host a few foreigners whose spare time is spent brushing up against each other in public places.
Andrew Marshall is a former foreign editor of The Independent who also worked for Kroll, a leading corporate intelligence firm.