Almost a year to the day after Ruth Davidson dramatically decided to step down as leader of the Scottish Conservatives, her successor has done the same.

Jackson Carlaw, who stepped in as interim leader before being effectively crowned in a lopsided leadership contest against Michelle Ballantyne in February, has decided that he is not the man to lead the Tories into the 2021 Scottish elections.

The immediate result is a great deal of confusion. As the Scottish Tories have two deputy leaders, at the time of writing not even the MSPs know who is stepping up as deputy leader.

More uncertain still is the question of who will succeed him. There is no obvious dauphin amongst the Scottish Parliament group, many of whom were only elected in 2016.

Adam Tomkins, one of Ruth Davidson’s most high-profile allies, is stepping down in 2021 (as is Davidson herself, at least at the time of writing) and in any event had perhaps blotted his copybook by toying with Murdo Fraser’s old idea of breaking away from the Conservative Party. (The band of Scottish Tories who believe in this plan didn’t field a candidate in February – will they this time?)

Twitter, meanwhile, is abuzz with speculation that Douglas Ross, the Member of Parliament for Moray, is about to throw his hat into the ring.

Ross, who was reportedly Davidson’s preferred successor before winning his Westminster seat, resigned from the Government in May rather than defend Dominic Cummings. This may give him some distance from the Government which may help him with Scottish voters who haven’t warmed to Boris Johnson. There is also precedent for an MP simultaneously sitting at Holyrood for a time – Alex Salmond did it between 2007 and 2010.

But would the man Downing Street sources branded ‘Mr Nobody‘, and who split with the UK close-knit leadership, be able to count on the support he’ll need from the UK Conservative machine?

All of which leads to the question of how the transition should be managed. With less than a year to go until what could be a make-or-break Holyrood poll the temptation to avoid a full contest will be strong.

But there is also a case to be made that the Party needs a fuller debate about where it is and how it got here. Carlaw’s resignation follows the planned departures of both Davidson and Tomkins and the stepping down in January of Eddie Barnes, the Tories’ long-serving ‘top spinner’.

The machine which delivered their stand-out 2016 result, of which Davidson was a necessary but not sufficient component, has been shedding parts for a while. A new leader is not the whole solution, any more than the old one was the whole problem.