Last week, I took part in a debate about notions of leadership, as part of the Festival of Ideas. The excellent Claire Fox, who runs the Institute of Ideas, gave the panel a restless brief. Do we have too much leadership or too little? Is it a sign of confidence to "outsource authority" to the public – or an indication of cowardice?

The libertarians argued against the nanny state, while my fellow panellist, Maj-Gen Andrew Ritchie, former head of Sandhurst, reminded us of the moral charisma of leadership. Humanity is drawn to great leaders and will follow them, even if it is against their self-interest, which, in the army, can mean their own lives.

Had we known the results of the US election by then, we could all have been more sanguine. Here was a perfect harmony of the leader and the led. An inspirational figure and a voting public mature enough – deserving enough – to appreciate it. The preciousness of democracy was on display to the world. As president-elect Obama said: "This is your answer."

Which brings me seamlessly to Daniel Evans and the audacity of mediocrity. Daniel is a tubby 38-year-old who, against all rational odds, was back on The X Factor last night. He has seen off the young, the fit and the gifted. Simon Cowell and Louis Walsh, two of the judges, have been in a state of dazed despair over his progress. Cowell behaves like a business mogul hearing that an idiot in reception won't leave. He is halfway to calling security. The X Factor is a great deal more than entertainment to him, it is a form of alimony. He needs to produce stars. And the public have been wrecking the business model.

The pool cleaner from Walthamstow served his purpose in the early rounds. He was a nice, ordinary bloke, whose wife had died. He produced the trickle of tears from Cheryl Cole that made every male viewer want to comfort her somewhere private. That marked the eclipse of poor Dannii Minogue, who could only glisten and tremble. And some belated emotional rivalry from Louis Walsh, who first insulted Daniel as an end-of-the-pier entertainer, then crumpled and sobbed like an Irish barmaid when Daniel sang a song with feeling.

As commercially viable stars such as Diana Vickers and Laura White emerged, so the support for Daniel remained steadfast. The public, it became clear, were not going to vote him off. The resilient charisma of Daniel lay in his ordinariness. While the edgy, good-looking contestants developed diva throat conditions and broke down with nerves, there was Daniel with his slightly wounded grimace. Only Dannii spotted the chance of a fightback. What is so wrong with the mediocre? Suddenly she was encouraging the audience to rise up against the snooty judging panel.

The public comments on the X Factor website have been hilariously subversive: "Daniel, you deserve to win." This, of course, is democracy in action. Sometimes it is fair, sometimes outrageous. At the IoI leadership debate we discussed the curious success of Gordon Brown in turning personal adversity – too old, too gloomy, too indecisive – into vote-winning leadership. The public mood changed. Democracy is the worst possible system (except for everything else), but it is invigorating to watch it in action.