So this is what the eclipsing of American power looks like, with the disgorging of so much of its sensitive diplomatic correspondence in one fell swoop. Arguably not since Berlin fell to the Red Army in 1945 has there been a compromise of state secrets as breathtaking as that brought about by Wiki-Leaks. Yet while the drift of much of the ensuing commentary has been that there is not much new in the 250,000 leaked cables, the truth is that the damage to American credibility and diplomacy is incalculable.

Amid all the WikiLeaks’ admirers’ trumpeting of the virtues of transparency, we risk forgetting the worth of diplomatic “back channels” – a strictly private way of communicating with the president of the United States. Normally this is done through visits to Washington, or the president visiting another head of state. But in between times there needs to be a trusted emissary, someone with a personal connection to the president; someone who can keep his mouth shut. When I worked for the Central Intelligence Agency I saw how important this could be.

I was in Europe in the late 1980s soliciting the co-operation of an Arab businessman, who was related to his country’s president. (I cannot name the country because even after more than 20 years this connection is still considered sensitive, a point that should seem all the more germane given the manner in which the intimate thoughts of Arab leaders have, courtesy of WikiLeaks, been bandied about on the front pages of the world’s newspapers.)