“It’s the economy, stupid”.

James Carville’s famous maxim from Bill Clinton’s winning campaign of 1992 became an accepted truth of modern politics.

If you had to come up with a single reason for the outcome the independence referendum then that would have to be it.

The setting up of the SNP’s Growth Commission was an acceptance that, for all the ‘uplifting vision’ and campaigning of how much better we could be as an independent nation, most Scots looked at the bottom line and firmly but politely said, no thanks.

That, of course, was a generation ago, apparently.

Read more: Independent Scotland can rise above Brexit-style row, report insists

Last weekend the First Minister announced her intention to reopen the debate on independence - as if it had ever been allowed to close.

Yesterday we saw the report of their Growth Commission. After the White Paper of 2013 this is supposed to be more of an “off white paper”.

White with a hint of realism. If Mhairi Black couldn’t bring herself to quote the last one, then it shall be interesting to see what she has to say now.

The Growth Commission Report has left more people scratching their heads than applauding.

Read more: Kenny MacAskill: Growth Commission is a substantial contribution but the court of public opinion will decide

Their latest magnum opus may be a tacit admission of the weaknesses of the case that they argued four years ago but there is no hint of an acknowledgement of the divisions that are left following our last canter round this course.

Nationalists will say that the 2014 referendum changed Scottish politics. They are right.

What they do not seem to have grasped is that the process of change did not stop on 18 September 2014.

Read more: Jim Sillars: Growth Commission has depth, detail and intellectual rigour

Almost four years later the people of Scotland are increasingly sick and tired of a party that cares far more about delivering independence than looking after our schools, hospitals and policing.

The new report actually tells us more about what the nationalists were wrong about in 2014 than anything else.

Despite years of taking a swipe at the credibility of the GERS figures, they now seem to agree that GERS are appropriate assessment of Scotland’s current fiscal position.

Also, they seem more firmly fixed on an independent Scottish currency, against economic sense and the will of voters who want to keep the pound.

But it is a “Panama Option” - using the pound without controlling it.

This time the “vision” is of independence where all the decisions about currency and interest rates are made in a foreign capital (as London would then be).

An independent country which does not set its own interest rates does not sound very independent to me.

For the SNP, however, the working definition of independence is any set-up that does not have us in a Union with England.

The nationalists, of course, will tell you that Brexit has changed everything and that is why we now need to reopen old wounds.

They may be right but not in the way they think.

Read more: John Curtice: Growth Commission is a bid to find answers but necessary steps won’t all be popular

If Messrs Fox, Gove and Johnson get their way then we may be about to see the damage that can be done to an economy that accounts for 15% of our exports.

That being the case I cannot think that there will be much appetite for removing ourselves from the single market that accounts for more than two thirds of Scotland’s exports.

Now more than ever, pro-EU and progressive actors across the UK should be setting aside their party loyalties to meet the real challenge facing the country; an incompetent Tory Government stumbling towards a hard Brexit.

The SNP have dropped the ball on education, on mental health, on improving services and growing the economy, but they could still get this one right.

If they truly believe in defending Scotland’s interests, they should be fighting for people across our isles to have the final say on Theresa May's Brexit deal and the chance of an Exit from Brexit.

Alistair Carmichael is the Lib Dem for Orkney and Shetland and was the Secretary of State for Scotland in the Conservative-Lib Dem coalition government