David Miliband's decision to abandon British politics and move to head an American charity can be interpreted in two ways. Some will see it as and act of heroic self-sacrifice to enable his younger brother to lead the Labour Party without constant press sniping about sibling rivalry. Others will see it as akin to the pique of the schoolboy who refuses to play the game if he can't be captain.
Despite the attempts of Labour luminaries, particularly of the Blairite wing, to push out PR in favour of the former, I suspect the bulk of the electorate will take the latter view. After all, when our prospective MPs face the electorate they promise effusively that the welfare of their constituents is, or will be if elected, their number one passion in life. In government, as Miliband has been, they claim that the interests of the British people are paramount in their thoughts day and night. So what's so different if you come second in your bid to lead your party?
There are many examples of politicians who have failed in their bids for leadership continuing to give service to their parties and government, albeit some with more distinction than others. R. A. Butler failed not once but twice to gain the Tory leadership, yet made one of the most significant contributions of any politician of his day and is fondly remembered, even by non-Tories, as "the best prime minister we never had." Another "best prime minister we never had" was Denis Healey, who still makes shrewd contributions to the economic debate. Sir Alec Douglas Hume was, I believe, the first post-war politician to accept a subordinate post after having been prime minster. Though neither was prime minister, Michael Howard and William Hague, both former leaders of the Tory party, soldier on in subordinate capacities..
After complete indifference, in my experience the most common response to political canvassers on the doorstep is: "You're only in it for what you can get out of it." David Miliband's departure will, I regret, reinforce this view: he hasn't got what he wanted so he doesn't want to play any more.