Peter M himself does not enter that debate, instead shrugging off the experience of "having my head shot off by all sides" for expressing a view with a "plus ca change" in a rather delphic commentary piece for Saturday's Guardian.
The piece may be capable of different readings, and I was not entirely clear as to its meaning on a first reading. Part of the purpose is to get closure on the final tensions of the leadership election itself.
So, overall, Mandelson combines something of an olive branch of constructive support for the new leader, while reserving the right to be sometimes critical in response to events, with a rallying call for a New Labour version of "new generation" politics, perhaps aimed at the next generation coming through the party after that of the Milibands.
So Mandelson wishes the new leader's next generation well, warning against straying too far from the New Labour script, while accepting the need to call it something different.
He argues that Ed Miliband's victory under the rules of the election contest must be considered legitimate, while entering the caveat that this would not be considered publicly legitimate if the party was in power and choosing a Prime Minister.
And Mandelson (here perhaps breaking with the Blair analysis in 'A Journey') seems to accept that New Labour ran and lost as New Labour, largely because what New Labour was by 2010 was far from clear to anybody, and had lost the ability to connect
Before this year's election we lost touch with the electorate. The world had moved on from the mid-90s New Labour mantras. But also we lost New Labour's ability to speak the language of fairness to a squeezed "middle Britain". The public found it harder to understand what a vote for New Labour meant any more.
This is, largely, a Mandelson gloss on Ed Miliband's central narrative about why New Labour was successful and where it went wrong, though the contentful analysis of how much and what needs to change may well be different.
Mandelson accepts too the arguments that New Labour became too much an administration in power, too little a political force - "We used fear of being accused of factionalism as the excuse. But the real reason is that we enjoyed government too much, from the prime minister down", in writing that:
We who created New Labour need to be far more self-critical. We did not do enough when we had the chance to put down strong enough New Labour roots.
"New Labour is dead; long live New Labour" appears to be the central message. Along with the fact that, with the post-New Labour debate up for grabs in the party, the message that "the torch has passed" also signals that Peter Mandelson does not intend any retirement from the political fray for quite some time.