David Miliband is absolutely right to argue for a system of registered party supporters, as in the United States, in his article in Tribune (ironically not online, though significantly a Tribune leader attacking him is!).
As with most parties, Labour has been rapidly losing members in recent years, as its dated ways of doing business slip into increasing irrelevance nearly a decade into the 21st century. What Miliband is proposing is not a free-for-all as with the Tories in Totnes, but a system of registered supporters who vote in primaries, and are presumably available for invitation to fundraising and other events.
It was dispiriting to hear Neal Lawson, once a serious moderniser, defending the status quo - albeit with PR whichI support - presumably in the knowledge that a smaller party may be more likely to succumb to vote-losing ideas, as it did in the eighties. It is simply untenable to expect that the only people who should have a view on Labour's candidates are those who turn up to hear the minutes of the last meeting read before the guest speaker from Compass or the self-styled Campaign for Labour Party Democracy drones on about the evils of a three-term Labour government and the wonders of Hugo Chavez.
If politics is to regain a relevance in people's lives, we need simpler structures and much more flexibility about how people can register their support and get involved.