Yousaf's departure is necessary, but is only one-half of what is needed - if a low-grade continuity leader is selected to replace him, the independence movement will be in an even deeper hole

It's no secret that I've wanted Humza Yousaf to resign from literally the day he was elected.  I was constantly told that there was no chance of that happening before the general election, and my reply was always that it quite simply needed to happen before the general election, otherwise the SNP were going to get hammered.  So in a sense his departure today might look like a dream outcome, but it's only half of the necessary equation - if the SNP replace him with someone even worse, such as Jenny Gilruth or Neil Gray, today will be a further setback not a step forward.  And that's particularly the case given what might be called the "Truss effect", ie. it's possible that a leader can be so disastrous that they have a severely negative impact on the fortunes of their successor, so whoever takes over may need to be an exceptional leader, not a workmanlike stopgap.

This depends of course not only on whether the SNP are willing to choose the right sort of person, and not only on whether the continuity faction will once again throw procedural dirty tricks in the way of the right sort of person, but also on whether the right sort of person is actually willing to put themselves forward.  We all understand that Kate Forbes is a young mother and thus has personal as well as political considerations to take account of, but if she wavers at all about running, I hope people close to her will tap her on the shoulder and say "your country needs you".  We're in an emergency situation, and if Forbes doesn't stand, the consequences could be incalculable because we're likely to end up with a low-grade leader from the continuity faction.

One thing I'm fairly sure of is that there won't be an early Holyrood election now.  Stuart Campbell is trying to make the logic of the situation fit his desired outcome and thus is insisting that if Yousaf resigns, the Greens and Alba are both likely to still vote in favour of Sarwar's motion of no confidence in the whole government.  I very much doubt that - I think the Greens will abstain and allow the leadership election to run its course.

And naturally there are commentators who are suggesting that if Yousaf prefers resignation to a deal with Alba, that must mean Alba are toxic in the extreme.  More realistically, it actually means Yousaf or someone advising him can count, and has worked out that a deal with Alba would only get him to a 64-64 split in the chamber - which would be enough to save his bacon this week, but wouldn't be enough to pass legislation or Budgets.

Ultimately we're in this mess because the

ruling faction wouldn't allow the leadership election last year to take place on a level playing field, and insisted on a loading the dice in favour of a wholly unsuitable candidate with abysmal public approval ratings.  The independence cause has been paying the penalty ever since.  I beg of our friends in the SNP to use this golden opportunity to repair the damage, rather than digging the hole even deeper.