Even more telling than his audience’s response to this, however, was what happened when Obama referred briefly to the need to develop “clean energy on enough public land to power three million homes”. But no mention now of vast numbers of wind turbines – those props beside which he constantly chose to be filmed back in 2008. No harking back to his boast that “renewable energy” would create “four million jobs”. And even to this sole fleeting reminder of what, four years ago, was his flagship policy the response of Congress was a deafening silence.

A few months after Obama entered the White House, I suggested here that the slogan on which he was elected – “Yes we can” – seemed to have changed to “No we can’t”. It was already obvious that, having won election as an ideal Hollywood version of what “the first black President” should look and sound like, he was in reality no more than a vacuum. His speech last week was as weaselly as any politician’s performance could be, not least in its references to the sub-prime scandal.