And so she's gone. Why now?
Why does Wendy Alexander resign over a minor slap on the wrist from a Parliamentary committee - when she was prepared to tough it out over what one of her team admitted was a breach of the law?
The cumulative effect, of course. But, more, it reflects the varying psychological response from Ms Alexander.
When it was disclosed that her campaign had received an illegal donation from a Jersey businessman, her first reaction was dismay.
She thought, seriously, she had to quit.
Then dismay turned to anger as she felt she had to fight back against her accusers.
Dismay to anger
This time round, she has gone in reverse: from anger to dismay.
She watched on Thursday as Holyrood's Standards Committee voted to suspend her for a single day because she had failed to declare campaign donations timeously on her register as an MSP.
She watched in mounting fury. She thought it a politically inspired stitch-up. Her aides were similarly angry.
David Whitton MSP strode down to the Garden Lobby at Holyrood to deliver an irate rebuttal. He was visibly tense.
Anger to dismay
She felt she had to go, she felt it was never ebbing away as an issue, she felt she had let down her party. Inadvertently, she believes. She resisted pressure from the PM to stay.
And so she's gone, blaming an unyielding pursuit by relentless SNP rivals. Does that quite work for you as an explanation?
I must confess it doesn't do it for me.
Politics is a rough trade: it is customary to expose weakness. It is part of the adversarial nature of party debate.
Did Labour hold back when John Major was under relentless pursuit? OK, so that was bigger league.
Did Labour cry foul, then, when David McLetchie, the Scottish Conservative leader, was facing criticism over taxi bills?
Wendy Alexander's campaign team sought donations from the business sector to fund her efforts to become leader.
Quite unnecessarily, as it turned out, because she was uncontested.
Was it, perhaps, superfluous in any case? Were the members of Team Alexander perhaps seduced by the thought of entering the Premier Division of politics, with premier division funding to match?
Couldn't they have got by with a series of hustings around Scotland?
After all, the Scottish Labour Party is, these days, relatively small.
She wasn't fighting a general election, simply an internal party contest.
Were members of the inner circle trying to show the extent of their clout: look at me, I can bring in big (OK, medium) bucks from serious business players.
Did the SNP pursue this relentlessly? Yes.
However, one of those donations, from a Jersey businessman, was illegal.
One can talk about mitigation, one can talk about who knew what and when.
One can point to the MSP, Charlie Gordon, who solicited the donation. But, as Tom McCabe conceded, the law was broken.
Separately, the issue of registration. There it is possible to evince more sympathy for Ms Alexander.
She was advised, in writing, by Parliamentary officials that she did not need to register the donations in her capacity as an MSP.
She followed the code. She followed procedure. With one rather crucial exception. By the time she sought advice, the deadline for registration had already passed with respect to at least some of the donations.
Then the issue of the ruling by the Standards Commissioner. He disagreed with the advice from the clerks. He said the donations should have been registered. They were tantamount to gifts.
Again, couple of points. Ms Alexander could have forestalled all of this had she over-complied: had she registered the donations, regardless of the advice.
Further, it seems to me that the system is slipshod and open to confusion.
It is not sufficient, I would submit, to determine such a relatively important matter as the registration of campaign donations on the basis of a few lines in a casual e-mail from a clerk, albeit on the basis of legal advice.
If such guidance is to be robust, it should be seriously scrutinised and delivered in a style that suggests it can withstand alternative interpretations.
In short, such guidance needs to show the arguments deployed, needs to show the working.
Further, the Standards committee at Holyrood looked, to me, uncomfortable in dealing with this issue.
Perhaps it was the partisan pressures involved, perhaps it was the political reputations at stake.
But they looked and sounded unhappy and unsure.
If this was a breach of Parliamentary rules by a party leader, should it not have merited more than one day's suspension? If it wasn't such a breach, because of mitigation, should it not have been dismissed?
Finally, the Labour Party. Not good for them, not good at all.
Doubt if they'll be reprising the old ditty "things can only get better" any time soon.
Wendy Alexander's leadership failed. She failed to counter Alex Salmond in the chamber. But will others do better?
She failed, fully, to persuade the party, especially the Prime Minister, to endorse her strategy of countering Mr Salmond with an early referendum on independence.
However, more than many others, she got the concept of the challenge facing Labour in Scotland.
Before the rest, she acknowledged that Labour lost - and deserved to lose - to the SNP.
It wasn't a fluke, it wasn't a swizz, it wasn't a temporary blip. It was a defeat at the hands of the voters.
Before the rest, she argued that Labour required to stand up ineluctably for Scotland - even if that meant standing against London, including the PM.
She recognised that Scottish Labour had to back David, not Goliath.
As of today, the slingshot has come her way.