Why do Ed and Len seem to 'agree'?
"A defining moment" said a man who's said almost nothing in praise of his party in recent years.
"A bold and brave speech" said another who disagrees with him about virtually everything in politics.
So, how can it be that Tony Blair and Len McCluskey, the leader of Britain's biggest trade union, do appear to agree with Ed Miliband's proposed reforms.
One reason is that they share the view that the status quo isn't working - though they do so for very different reasons.
The historic relationship between the unions and the party it founded does not give Labour the day-to-day contact with ordinary working people which it craves. Equally, it doesn't give the unions the influence or the power they think they deserve.
Another reason is that there is, as yet, no detail, let alone agreement, about how this proposed rule change will work in practice, nor when it will happen, nor what its implications will be for party funding or union votes in selection contests or at party conference or for the next leader.
Mr Miliband doesn't even try to deny that the crisis over the selection of a candidate for Falkirk inspired this initiative. He says he's seizing the moment.
Few doubt that but - with the GMB leadership understood to be furious at the proposals - there are clearly many more than two views tonight about exactly what these changes will mean in practice.
Last night I reported that Larry Whitty had been asked to negotiate the detailed changes to the relationship between Labour and the trade unions. Labour insisted that he was not the man being given that job.
I now understand that Lord Whitty turned the job down as he feared that Ed Miliband's plan was not deliverable and that the necessary ground work for it had not been carried out.