Has big brother David read little brother Ed's electoral analysis?

The central argument between the Miliband brothers has been about Labour's election strategy. Their debate about why Labour lost and how to win being the subject of a major speech from each brother in the last week, as well as interventions from Lords Mandelson, Kinnock and others.

Many people have noted the danger that the campaigns are talking past each other.

One reason why could be spotted in the course of David Miliband's Guardian interview with Decca Aitkenhead yesterday.

"Yes, we lost 1.6m votes among DE voters, as they've advertised," he says – referring to his brother's team. "But we lost 2.8m votes among C1s and C2s" – the Middle Englanders who delivered Margaret Thatcher's landslides – "who apparently were left out of his table. He compared DEs to ABs – and yes, we've got a real issue among DEs, we've got to get those votes back. But we lost 2.8m votes among C1s and C2s combined. Of course we lost fewer ABs – because we had fewer of them to start with. But we've got a 16% lead among DEs."

The tell-tale "apparently" suggests that this is a second-hand point, with the candidate unusually uncertain of his facts. It suggests that the elder Miliband did not look at his brother's analysis himself, and is instead relying on what his campaign aides have told him about it? Alternatively, he may have misremembered.

Whatever the explanation, David M would appear to have been misinformed, since that claim is clearly wrong.

The table of electoral analysis published by the Ed Miliband campaign - Analysis of Lost Voters (PDF file) clearly set out the change in AB, C1, C2 and DE vote shares in 1997 and 2010. The loss of C2 and C1 votes was prominently highlighted as a headline finding by the campaign on the day of its release, alongside the DE analysis. One later table which shows how the fall in DE votes alone affected the 2010 share, but that can't stand up the idea that the loss of the C1 and C2 voters was omitted from the analysis.

The analysis was published by Left Foot Forward: the "evidence-based" blog may perhaps be disappointed to see the David Miliband campaign not paying more attention to the evidence. This coincided with the publication of Ed Miliband's Fabian Essay, part of the collection to which all leadership candidates have contributed.

Perhaps the claim that the C1s and C2s have been ignored simply reflects a political decision to sharply polarise the argument about electoral strategy, characterising the competing analysis as the case for a "core vote" strategy. Yet, on the face of it, the comment implies that the candidate hasn't read the analysis which his campaign is rejecting.

The electoral strategy debate is important, but it is considerably more nuanced than those offering daft caricatures of "Red Ed" or David as an "uber-Blairite" suggest, and perhaps more nuanced than the campaigns themselves want to admit too.

It is perfectly clear that neither candidate thinks that electoral success can be done on so-called "core votes" or "middle-class" votes alone, though the question of whether it makes any sense to talk about a "core vote" given how Labour's vote fractured is one of the central arguments in the debate.

It is fair to say that the thrust of Ed Miliband campaign's political argument was that New Labour had failed to realise how much its DE vote had slumped, and the impact of that on vote share and seats. The David Miliband campaign agrees that these votes matter, while placing more emphasis on lost C1 and C2 votes and maintaining a strong middle-class appeal, warning against pretending that these don't matter. And, of course, the Ed Miliband campaign has had a strong focus on middle-class votes too - though suggesting the loss of twice as many AB votes to the LibDems than the Tories suggests that New Labour was too dismissive of civil liberties and foreign policy concerns, and will need to rethink those issues to recover ground among the middle-classes too.

Each of these debates matters - and a robust debate during a leadership contest is fine - but lets try not to caricature it. David Miliband supporter Tom Harris is quite right that coverage of the argument implying the party is descending into civil war is absurdly hyperbolic and ahistoric. Both Lords Kinnock and Mandelson know enough Labour history to make a letter to the Times a most unlikely way to kick a Labour party civil war.