So why did he agree to enter a forum – the prime ministerial debates – where he was going to be at an immediate cosmetic disadvantage against two younger, better looking, more articulate rivals? None of the main Labour Party strategists is going to disclose his thinking until after the General Election, not least because the decision will be vindicated or condemned solely by the result, not by snap surveys conducted in the immediate aftermath of the debates.
Prime ministers, sensibly, have always opted to wrap themselves in the mantle of authority that the office confers. But this time Brown caved into the media pressure that was mounted for leaders' debates. The fact that this campaign was led by Sky News should have put him on his guard. Rupert Murdoch's empire was never going to do him any favours. The Sun had already come out in favour of the Conservatives. Clearly, it was thought that forcing Brown to risk exposing himself to being examined live on television could only turn out to his disadvantage.
One explanation as to why he gave into this pressure is that at the time it was being applied, he was so far behind in the polls. He felt that he had nothing to lose. But his advisers must have seen him suffering week in, week out at Prime Minister's Questions and realised that he simply has not got the fleetness of mind to respond spontaneously. The more troubling question is why he was not able to see that for himself. We are told that Brown has been debating since he was at school. How come, then, he was so uncomfortable in the televised format?
Of course, he was always confident that when it came to substance, he would hold the advantage. But as Tony Blair so accurately pointed out, his substance is of the clunking fist variety. He may be right, but he doesn't convince. The audience doesn't warm to him.
After the negative reception of his showing in the first debate, Brown was reduced to trying to explain away his lack of charisma – "if is it's all about style and PR, count me out". But in our increasingly presidential style of elections, looking good is part of being a political leader. If you haven't got it, you really can't expect voters simply to overlook it.
But why did his strategists ever expect voters to judge the debates on who had the more substantial arguments? From the very first Kennedy/Nixon TV debate, it has been recognised that it is appearance and presentation that count. Those who listened on radio to that first Kennedy debate thought Nixon had won. It was only when television viewers were polled did the opposite verdict emerge. Since then, the smart money has always been on style winning over substance every time.
One suspects that the main problem is that the English don't really like Brown. At the start of this campaign Brown paraded his team in Downing Street. But since then we have seen precious little of it – especially the women. By offering himself as the sole front man to an audience who is distracted by his appearance, he is obscuring the message – a message that must be heard in the marginals.
But despite these misgivings, I am not yet prepared to say it was a mistake for Brown to agree to the debates. We will not be able to judge the efficacy of his decision to appear until after the election. If the boost they have given Liberal Democrat leader Nick Clegg results in Labour having the largest number of seats, it will be regarded as the right decision.
Going into the campaign, Labour could not have hoped for better than a hung parliament. Even if Labour achieves that target but comes third in the popular vote, then it would still not be a disaster. In that case, the Lib Dems might – if they are very brave – stick to their leader's promise and offer a coalition, as long as Brown does not lead the government.
The alternative of a minority Tory government might just be sufficient to persuade Labour's National Executive to ditch the rules on leadership change and advise the parliamentary party to appoint Alan Johnson or a Miliband – but not, please not, Ed Balls – as leader.
Given yesterday's amateurish gaffe on Mrs Duffy's doorstep, poor old Brown must be wishing he could get a sick-line and scupper tonight's debate. What he must do is put on a brave face, tear up his speech and rehearsed ad-libs. If he strips away all artifice and talks directly to voters from his heart, you never know, it might still be all right on the night.