Rupert Cornwell: Don't blame diplomats – they come out of it well

A diplomat, an English ambassador to Venice famously declared, is "an honest man sent abroad to lie for his country". If so, then the WikiLeaks revelations suggest that the early 21st-century American practitioners of this delicate trade have done a pretty good job.

Washington is furious. It mutters about prosecuting Julian Assange. Hillary Clinton has rightly warned that US diplomats will face a much tougher task in future. America's government, less well informed about a hideously complex world, will also be a loser.

And so, in the longer run, will be the media. Secrecy will grow, security classifications will be raised, and the public will know less, not more, about what the diplomats are doing in its name. Which will be a pity – because, for the most part, they are as serious and skilled a bunch as you could wish to find.

The State Department has been accused of not fighting its corner and of losing morale after being repeatedly steamrollered by the infinitely better funded Pentagon. You wouldn't notice from reading the cables.

Only a fraction of the 250,000 cables in WikiLeaks's hands have yet been released. But the diplomats' behaviour has been highly professional and their attempts to solve problems sincere. And the judgements on events and people – some so titillating to read – are usually on the money.

Remember, too, that diplomats facilitate and execute their governments' policy. Rarely do they make that policy. You can argue that the US should get out of Afghanistan, or that Washington shouldn't prop up authoritarian regimes in places like Saudi Arabia, and that no one should have illusions about Putin's Russia.

The cables show that they weren't peddling those illusions. Rather, they were trying to alert their political masters about the dangers. If it had been left to the State Department, the disastrous 2003 Iraq war would not have happened.

Some of the leaks may actually have strengthened the US hand. If anything, the fear of Iran throughout the Arab world, now public knowledge, may help the US as it presses for ever tougher sanctions against Tehran. And if unvarnished US views of Silvio Berlusconi hasten his exit, few will shed tears. Even so, it's very hard to argue that the public interest has on balance been served by these disclosures – let alone the interests of the US.

However, the damage is not the fault of America's diplomatic service. What needs overhaul is an insane government network for classified information that permits a disturbed 22-year-old army private to have access to his government's most sensitive international dealings.