When a senior MP walks out of his party four months before a general election, he makes it obvious he does not like its chances. Shane Jones has done Labour no favours by quitting so late in the day. If his unsuccessful bid for the leadership last year was decisive for him, he would have left at the end of the year, or perhaps after reflecting over the summer break.
Instead, he came roaring back to Parliament in February, accusing the supermarket chain Progressive Enterprises of extortionate dealings with local suppliers and prompted the Commerce Commission to announce an inquiry. He was outshining his party's chosen leader, David Cunliffe, and looking every inch the leader it should have chosen. But over Easter he decided to pack it in.
Sometimes it is the prospect of success that prompts a person to re-assess his career. If the coming election turns out badly for Labour there is every prospect it will blame Mr Cunliffe and look for a new leader.
Mr Jones had to consider whether he really wanted to be that leader. He stood for the job last year without much hope of success. He seemed less than serious, almost a self-parody at times. But in standing he put the hotel porn incident behind him and restored the high expectations once held for him in politics.
He had been called a future Prime Minister. Mr Jones had the stature and personality to compare with Labour's Norman Kirk and David Lange. But he has not looked comfortable in the Labour Party for a long time.
He is a no-nonsense believer in industry and jobs, not the environmental causes, gender balances and diverse identity politics of Labour today.
Mr Jones tasted corporate life as chairman of the Maori Fisheries Commission before entering politics and clearly still enjoys the company of business leaders. In politics he has put development, particularly for Northland, ahead of all other concerns and made no secret of his distaste for the Greens. His campaign for the party leadership emphasised Labour's need to win at least 40 per cent of the vote at this election so that it would not be too dependent on the Greens. Clearly he sees no prospect of Labour lifting its vote to that level now.
If the election does put Labour in a position to form a government, it will be heavily beholden to the Greens. On paper New Zealand First could be an alternative coalition partner, one that Mr Cunliffe, like Helen Clark, would probably prefer to the Greens, but Mr Jones knows Winston Peters better than most people and obviously does not think Mr Peters would put a second-placed party in power.
All things considered, he would sooner accept Foreign Minister Murray McCully's offer of a roving ambassador's role in the Pacific.
He will keep an eye on economic aid projects in the islands, an interest he has demonstrated on a previous Pacific tour with the minister. It looks like a job created for him, though it does not sound so compelling that it could explain his decision to leave politics.
He is leaving for the reasons he gives: "I don't want to do it anymore ... I'm not able to give to Labour the 100 per cent that I ought to be giving. I want to go and do something else."
It is a body blow for Labour so close to an election. If the party cannot excite one of its own, an MP who could count on being in its Cabinet if it becomes the government, how can it excite the voters on September 20?
Labour has not only lost an effective MP but has also lost one of the few who could reach into the male, blue-collar enclaves Labour used to command. It has lost a dimension.