In all US Presidential elections, campaign managers fear the 'October surprise'. By that they mean a late-breaking development that comes from nowhere and alters the trajectory of the November election. It could be a foreign crisis, a political scandal or an unscripted moment on the campaign trail.
There is nothing these insiders fear more than events they can't shape. For the strategists are, above all, control freaks.
Well, guess what? We've just had our October surprise.
We all projected that President Obama would win the debate. We've built him up - rightfully so - as the greatest communicator since Ronald Reagan. He has it all: touch, empathy, policy grasp, remarkable oratory, an intuitive grasp of the American dream.
And Romney? Well, we've ridiculed him for over a year. He is so awkward and over-scripted at campaign events even reporters feel embarrassed. His offer of a $10,000 bet to Rick Perry in a TV debate is still excruciating to watch.
So we knew Obama would win on Wednesday night.
Except it was October and we were in for a surprise.
I cannot explain what happened to President Obama. It's a political riddle and may remain so. Why did he not mention the "47%" secret video? Why didn't he take pride in saving the US car industry? Why not own healthcare reform? Above all, why not personalise his arguments, by talking of ordinary people's struggles and how his policies had helped?
He blew it in front of a TV and web audience of 70 million people. He has demoralised his supporters; mystified his handlers. One observer shook his head and described the debate as unilateral disarmament.
And with that weak performance the President has thrown a lifeline to Mitt Romney. Before the debate Mitt was a struggling candidate running out of oxygen.
Have the tables turned? Not yet. We've more debates, more twists to come, and the President is still ahead in key states.
But has the narrative changed? You bet. Romney no longer looks destined to lose. He has new bounce and energy. Money follows success. The American press has a story on its hands.
So with 31 days to go, we're about to find out if President Obama has fire in his belly; whether he will fight and scrap for a second term.
Or did the debate provide us with the greatest October surprise of all: the realisation that after four brutal years in office the President is not only defensive but bone-weary and out of ideas?