The world will see Clare Short's departure as another blow for the Labour Party brought on by Tony Blair's decision to send troops into Iraq. She is one of those rare politicians with star quality, not afraid to stand alone, whose unspoken opinions made sense to people who would otherwise have little time for politicians.
But not many Labour MPs will mourn the loss.
Never an easy colleague, Ms Short's sharp tongue and headstrong ways have left a trail of enemies. Her call for a hung parliament may seem uncontroversial to an outsider but to Labour MPs who want to hang on to their marginal seats it was like rank treachery.
Her relations with Tony Blair, which were never warm, had deteriorated into bitter recrimination. This year, she also fell out with Gordon Brown, once a staunch ally.
Her career has been marked by controversy. Arriving in the Commons in 1983, at the same time as Blair and Brown, she achieved celebrity status before either of them, when she accused a minister of being drunk at the dispatch box - a breach of Commons rules, for which she had to apologise. The minister was Alan Clark, whose frank diaries later confirmed that he had, indeed, been under the influence.
This was an early sign of Clare Short's fearless willingness to attack people big enough to hit back. Her targets included the Catholic Church, into which she was born, for its attitude to women and to abortion, and West Midlands Police, which she said was infested with corruption. Another target was Rupert Murdoch. Her campaign against The Sun's Page 3 girls opened her up to relentless abuse from the Murdoch press.
She also invited controversy by supporting the reunification of Ireland and the legalisation of cannabis, and she developed a lively contempt for the polished spin doctors who surrounded Tony Blair. By the summer of 1996, Mr Blair decided that she was too uncontrollable to be allowed a place in a future Labour cabinet. Then the whole of Westminster was taken aback when she revealed she had been reunited with her long lost son, born and given away for adoption when she was a student. The story stirred a wave of public sympathy and Mr Blair decided he would have to employ her after all.
She served six years as a respected International Development Secretary, presiding over a sharp increase in the overseas aid budget, while taking pains to make sure that the money did not disappear into the pockets of arms dealers or corrupt politicians. As the Iraq war approached, and it became increasingly likely that Robin Cook and other ministers were going to resign in opposition to it, she allowed herself to be persuaded by Mr Blair that she would have had a vital role in the reconstruction of post-war Iraq. She stayed in the Cabinet, and in the critical Commons vote in March 2003, she voted for war.
That was possibly the biggest mistake of her political career. Before long, she decided the Prime Minister had tricked her, and she left the Cabinet, saying she could not go on defending a war that she now regarded as "totally dishonourable".
Her anger increased over the next two years, and her attacks on Mr Blair became less and less restrained. Her estrangement from the party that she had served for a quarter of a century became so great that yesterday's resignation announcement took no one by surprise.