Ruth Davidson’s departure will leave Unionists and Tories scratching their heads.
And it is important to differentiate between those two groups, because the problems her departure creates are different for each of them.
Let us deal with the Unionists first. Ruth Davidson, in 2014, became the right person, in the right place, at the right time, and her outstanding performance in the Scottish independence referendum campaign, combined with the simultaneous collapse of Labour, made it abundantly clear to Scottish voters that she was the Unionist-in-chief.
At a time when Unionism had again become on-trend, that really mattered, and she exploited it brilliantly to keep Scottish public opinion Unionist, and to lift the Tory party on the back of it.
As the presumed head of the Unionist campaign in any future referendum, her departure now leaves a hole unlikely to be able to be filled by any other Unionist politician to the agreement of all others. It will, I suspect, force Unionists to turn to a civic or business leader to spearhead a coalition of Unionism.
The problems for the Tory party are different, but if anything more profound. One common misinterpretation of the Ruth Davidson years is that she fundamentally detoxified the Tories. She did not. Indeed she didn’t really try.
Instead, she relegated the Tory brand to the small-print, pushing instead the Unionist identity and herself. Why? Because she knew the Tory brand had not recovered and was not a vote winner, whereas she and Unionism are.
That is now the fundamental and existential decision for the next leader of the party. Is the future of Scotland’s centre-right as part of a UK Conservative party, or as a separate entity in control of its own destiny?
The direction of travel under each of those outcomes is very different indeed.
Andy Maciver is director of Message Matters