David Miliband's decision to quit parliament  removes him from the exquisitely tricky position he had been in since narrowly losing the leadership contest to his brother in 2010. From the moment of his defeat any intervention he made, regardless of the topic, was interpreted as part of a complex family psychological drama connected in some way with his thwarted ambition. That is partly because there was a cadre of senior Labour figures who doubted Ed’s capability to do the top job properly and privately toasted the elder sibling as a leader-over-the-water.
Once Ed had consolidated his hold on the leadership those dissenters who still questioned the strategic direction of the party focused their mutterings instead on the perceived failings of Ed Balls to advance a persuasive economic argument. David’s old cheerleaders downgraded their ambitions for the former foreign secretary and started toasting him instead as shadow-chancellor-over-the-water.
At no point did D Miliband give any public encouragement to that kind of chatter. I’ve never seen any evidence he nurtured it in private either. His deep irritation and frustration at the “pantomime” and “soap opera” that accompanied his every policy pronouncement always struck me as genuine. The awkward reality of his situation was that he had wanted only one job in the Labour party and it isn't vacant now or likely to be soon.
The line from Ed’s office has always been that David would be welcome in the shadow cabinet or in some other senior role but that was as much a statement of intent, necessary to show the will for fraternal reconciliation, as it was a plausible recruitment drive.
That doesn’t mean Ed’s hope of involving David was insincere. On the contrary, the Labour leader’s office is definitely in the market for substantial figures to bolster the frontbench. Some Ed Miliband allies are given to privately lamenting the weakness of the shadow cabinet and its shortage of people prepared to do “heavy lifting”. When I asked one senior Ed ally recently about David’s position I was told: “It’s crazy to have a star striker just sitting on the bench.”
But what would the elder Miliband actually do? In theory, he would need a role that boosted Labour’s chances of election without stoking mischievous chatter about recrudescence of sibling rivalry. That was clearly impossible. David had tried periodically to intervene and found that whatever point he was trying to make – on welfare, on Europe, on the economy – was interpreted as criticism of the choices made by his brother. He was typecast as the embittered Esau to Ed’s Jacob. Either that or it was configured as a move against Balls.
The longer this went on, the more irritating it became for everyone involved. Compounding that frustration is the stubborn salience of the family usurpation on the doorstep and in focus groups. It is one of those personal stories that, in pollster jargon, “cuts through” - a rare phenomenon when few things in politics resonate with a busy and mostly uninterested public. To Ed’s perpetual irritation, not being his brother remains one of the few things that people who don’t spend unhealthy amounts of time following politics actually know about him. For that reason I suspect David’s departure to US will be seen in the Labour leader's office as the least worst outcome now. One way or another, this was an issue that needed closing down and emigration achieves that goal, not perhaps as romantically as a great public reconciliation but quite effectively nonetheless.
There are quite a few people inside Labour who will be bitterly disappointed at David’s departure. One inevitable interpretation is that it cements the victory of the old Gordon Brown faction over the forces of Blairism. That is plainly the gloss Conservatives will gleefully apply. It is an interpretation that carries some resonance for the generation that bears scars from New Labour's epic vendetta.
On the night of the leadership election one of David’s closest supporters told me bluntly “the bad people have won.” It wasn’t an attack on Ed personally so much as an expression of rage at the way the trade union machine had been requisitioned to engineer the election outcome – or so the David camp saw it. The alternative view is that the older brother lost fair and square having fought entirely the wrong campaign, underestimated the party’s appetite for repudiation of Blairism and alienated one too many MPs and local party meetings by acting haughtily as if entitled to the crown.
That is all history now. The contours of allegiance that were so vivid then have already blurred and whole new squabbles, rivalries and ideological animosities have risen to take their place. That’s politics. There is always poison close at hand, it just gets transferred into differently shaped bottles. For the time being those bottles are firmly corked because the government is conspicuously failing and Ed Miliband has a fighting chance of being Britain’s next Prime Minister. For as long as that remains the case, Labour’s brittle unity looks set to hold. Hunger for power is proving more adhesive in papering over cracks than many inside and outside the party expected.
Whatever happens, it has been clear for some time that the next act in the Labour drama was being written without a starring role for David Miliband and he knew it. Since he had no lines in the script, no rousing soliloquies to deliver, he has sensibly chosen to leave the stage.