After decades of Conservative decline in Scotland, Davidson breathed life into a dying party, making it a viable force once more. She might not have won that election but pushing Labour into third place was a victory in itself.
It is undoubtedly true that Davidson is an unusually charismatic politician, a sleeves-up-let’s-get-on-with-it sort with a good line in self-deprecation and a grasp of the challenges facing families, right now. But personality can only get one so far. Davidson's success was founded on the strong and clear message that her party was firmly opposed to a second independence referendum. Married to that was her refusal to shy away from criticising the UK Government. When Davidson - a working class Fifer - insisted she had little or nothing in common with many of her colleagues at Westminster, there was a ring of truth.
And so, when Davidson stepped down as leader in 2019, she left a Conservative Party in better shape than it had been for decades. Not only that, she had shown any successor a clear way forward: stick with that anti-independence mantra and avoid looking like a poodle of the UK party and you’ll be okay.
After six months during which her successor Jackson Carlaw maintained the Davidson strategy, the Scottish Conservatives’ men in grey suits decided that, in fact, the party needed fresh leadership. The affable Carlaw was brutally ousted and replaced by the Moray MP Douglas Ross.
Ross, who had spent 13 months as a list MSP at Holyrood before defeating the SNP's Angus Robertson in the 2017 General Election, returned to the Scottish Parliament last year and his task was clear: keep doing what Davidson had done.
Instead, Ross has taken a match to the Davidson project and sent it up in flames.
And it had all been going so well.
Ross's decision, in January, to call for the resignation of Prime Minister Boris Johnson over the party gate scandal was a wise one. It placed him firmly on the side of the majority of Scots who remain firmly immune to the PM’s charms.
Then, in a decision which I suspect marks the beginning of the end of the Ross era, he changed his mind. In early March, he explained that, because of the Russian invasion of Ukraine, it would be wrong to change Prime Minister.
The use of war in Ukraine as a shield behind which Johnson could cower has been one of the more cynical acts of the PM’s snivelling acolytes. That Ross bought into the nonsensical idea that Johnson’s political survival was made necessary by Russian President Vladimir Putin’s aggression says a lot about him and none of it is good.
There can only be two explanations. Either his initial demand that Johnson should go was mere posturing or he is foolish enough to believe the nonsense that - at a time of international crisis - the lying incumbent of 10 Downing Street is the best man for the job.
Last week, former Tory MSP Adam Tomkins warned that the Scottish party has fallen into "terminal decline” because of Ross’s pitiful handling of the question of whether Johnson is fit to hold office.
It is difficult to disagree with Tomkins’s analysis that, having taken the "high road of principle earlier in the year", the party's stance on the matter now looks "not only empty but risible”.
Tomkins predicted that Scottish voters would punish the Conservatives in May’s local government elections over Ross's decision to back Johnson. I wouldn’t bet against that prediction.
Having made the foolish decision to withdraw his call for the PM to go, Ross had a brief window of opportunity last week during which he could have corrected that mistake.
Johnson’s appearance at a private meeting of Tory backbenchers went so badly that previously loyal supporters turned away from him. Showing no contrition whatsoever, Johnson lashed out at critics, urging colleagues to feel outraged at criticism by Archbishop of Canterbury, Justin Welby, of Government plans to send asylum seekers to Rwanda.
Rather than bringing the Tory Westminster group together, Johnson turned more of his colleagues against himself. A couple of days after the meeting, even MP Steve Baker - the right-wing libertarian who played a key role in bringing down Theresa May in order that Johnson could succeed her as Prime Minister - had had enough. It was time for Johnson to go. The gig was up.
Ross could - had he been a nimbler political operator - have used Johnson’s failure to convince backbenchers that he was truly sorry for the repeated breaches of lockdown laws in Downing Street as the reason he had, on reflection, decided it was time for the Prime Minister to go.
Instead, Ross said nothing. Johnson remains in office, for now, thanks, in part, to the support of Douglas Ross.
If the Scottish Tories - as they deserve to be - are overtaken by Labour in the council elections, Ross’s position will be all but untenable. And he’ll have only himself to blame.
Regardless, it’s now abundantly clear that Ross lacks the strength of character which made Davidson such a formidable leader of the opposition. He’s squandered any moral authority and reduced himself to the status of Johnson lickspittle.
As increasing numbers of Tory backbenchers question Boris Johnson’s fitness for office, it looks unlikely that he’ll lead his party into the next General Election.
If Tory MSPs have any sense, they’ll see to it that Douglas Ross doesn’t lead his party into the next Holyrood campaign. The way he’s trashed the Scottish Conservative revival shows he’s supremely unfit for leadership.