Those same diplomats and negotiators have seen the president struggle to make what, to outsiders, look like pretty reasonable changes to US healthcare. They have seen a summer campaign demonise him as an amalgam of Stalin, Hitler and Big Brother, bent on sending America’s frail grannies to their deaths in the name of a new socialism. If that’s the response he gets when he suggests Americans should be covered even when they change jobs or get sick, imagine the monstering coming his way if he tells his compatriots they have to start cutting back on the 19 tonnes of CO2 each one of them emits per year (more than twice the amount belched out by the average Brit).

Even if he was prepared to defy US public opinion, Congress wouldn’t let him. Remember, it was not Bush who killed the Kyoto treaty in the US. The Senate rejected it before the text had even been finalised, by a margin of 95 votes to none. Once again, if Obama cannot even get his healthcare reform through a Democratic-controlled senate, what chance a climate change treaty that goes beyond Kyoto? One European diplomat closely involved with the talks despairs at the “Republican headbangers who cannot resist a chance to damage Obama, believe global warming is based on junk science and regard action on climate change as ungodly because it will delay the second coming”.