The pursuit of independence is all that matters to the Scottish Nationalists.
It is the glue that holds together everything they say and do. Having lost the referendum on independence they wasted no time in predicting the circumstances in which another one could follow.
On the day after the EU vote, Sturgeon said that a second Scottish referendum was highly likely, and yesterday she set out exactly how she wishes to achieve it.
Some people say this is purely down to the Leave vote, and to be sure, it has given the SNP perfect cover under which to bring forward plans for a fresh poll, but if it wasn’t Brexit it would have been something else.
Alex Salmond said that a new vote would be likely if Boris Johnson became PM, or if the UK voted to renew its nuclear deterrent.
In other words, they were determined to find a reason and they would have done so at some point in the future. Nevertheless, the UK now faces once again the spectre of disintegration and Brexit will be the soundtrack to the coming battle.
Sturgeon has likened independence to a lifeboat for Scotland as the Tories sink the rest of the country with their pursuit of a so-called hard Brexit.
In reality, it is membership of the UK that will keep Scotland afloat.
Within hours of her declaration yesterday, the European Commission confirmed that an independent Scotland would have to reapply for EU membership – raising uncomfortable questions about the size of its national debt and the issue of joining the euro.
The SNP’s economic case for independence collapsed along with the oil price, and it’s hard to see how Scotland’s public finances could cope – at least in the short term – with a departure from the UK.
These are the arguments, so recently fought and settled, that now look set to be fought all over again.
While Westminster wrangles with the politics and process of any future vote, the case for the union must be made once again.
In Ruth Davidson, the Scottish Tories have a leader who can make the case better than anyone, but she will need support. A second referendum may be inevitable, but independence is not.