Fans of that great 1970s TV series Colditz will remember an episode in which an inmate tries to feign madness in order to get repatriated to Britain, only to actually go mad. I was reminded of this by Ed Miliband's speech at the weekend.

It contains sins of comission and omission.

The sin of commission is the economically illiterate statement "You and I know we won't have the money" and the very dubious "commitment to balancing the books in the next government".

I say this is dubious because it poses so many questions: why should it be fiscal policy more than monetary policy that tightens? What makes you so sure that we need extra tightening rather than just the operation of automatic stabilizers? Why should fiscal policy be time-dependent rather than state-dependent? What if growth slows markedly in the next parliament?

The sins of omission are that there are so many issues Miliband ducked, such as whether secular stagnation is a threat and if so what to do about it, and how he proposes to significantly reduce unemployment whilst tightening fiscal policy? And aside from a tokenistic promise to put workers onto remuneration committees, there was little interest in pursuing greater worker control or challenging managerialism. Yes, he's promising some income redistribution - but not, perhaps, very much.

There are, of course, good reasons why Miliband made these commissions and omissions. Leftist governments must work within tight constraints. These include the power of the rich which precludes a serious redistribution of wealth and power and the economic illiteracy of the media and voters who have swallowed half-witted guff about balancing the nation's books.

And this is where I was reminded of that Colditz episode. What worries me about Miliband is that he is not merely feigning madness in order to win votes but that he might have internalized the constraints upon him, and so he actually sincerely believes in tighter fiscal policy come what may and in only very gentle redistribution. As Nietzsche put it:

He who fights with monsters should be careful lest he thereby become a monster. And if thou gaze long into an abyss, the abyss will also gaze into thee. (Epigram 146)

My concern here isn't merely for Miliband's internal mental state - though I fear that he has internalized managerialist ideology. The problem is that when Labour leaders do internalize the contraints upon them they can end up missing the chances to make radical reforms on those rare occasions when the constraints fade. For example, in the late 90s Labour's massive majority and disarray of the Tories gave it a chance to pursue a genuine stakeholder (pdf) economy, which it fluffed. And in 2008-09 Brown missed the chance to place banks under democratic control.

The history of the Labour party, especially since the 1950s, has largely been one of disappointment to the left. The reasons for this aren't just structural, but also psychological.