Getting Brexit done was a major headache. But taking Scotland out of the UK and into the EU would be the mother of all migraines.
Brussels would insist Scotland treats England as a “third country”, which means fresh English sausages, live mussels, and unfrozen lasagne would be banned north of the border.
English dogs, cats and ferrets would have to be vaccinated three weeks before being allowed into Ms Sturgeon’s brave new world in accordance with EU regulations.
Sassenach racing pigeons would be frisked by unsmiling border guards because of EU animal health rules. And English racehorses would face new bureaucratic hurdles to clear before they could compete in independent Scotland.
Fortnum & Mason and Marks & Spencer hampers could be a thing of the past for Scottish households, as they are already in Northern Ireland, as businesses decide the red tape is not worth the hassle or cost.
Meanwhile, certain ‘dangerous’ English trees would be outlawed after the EU’s newest member state aligns itself with Brussels’ regulations on plants.
The UK left the EU, its Customs Union and the Single Market in 2020 after the Brexit referendum in 2016.
Ms Sturgeon wants to rejoin all three, which means any goods and animals travelling from England into Scotland would face border checks to ensure they meet EU standards.
The Irish Sea border has proved this greatly increases burdensome paperwork and pushes up shipping costs.
The new burdens are particularly heavy for smaller businesses, which will simply stop exporting to Scotland as some already have done to Northern Ireland.
The Irish Sea border exists to carry out the checks which would be too inflammatory to conduct on the invisible frontier between Northern Ireland and EU member Ireland.
But there is no convenient ferry crossing on the 96 miles between Marshall Meadows Bay on the east coast and the Solway Firth on the west to funnel the checks though.
The only solution to convince Brussels that the integrity of its Single Market would be protected would be a hard Scottish-English border, complete with checkpoints.
Even that would not protect EU territory from a wandering English cow meandering over the border without the necessary Brussels-approved ear-tag.
The SNP could argue that technology and digital customs procedures could smooth out the border friction. But Brussels rejected such ideas as “magical thinking” when the UK suggested them as possible solutions for the Irish border.
This doesn’t take into account any measures the UK might decide to impose on Scottish goods in response.
The EU will be less flexible with Scotland than it is over the island of Ireland. The Scots will not have the benefit of an EU member state like Ireland pressing the case for special treatment.
Outside of the UK, supplicant Scotland will be in no position to demand opt-outs from Brussels’ rules as it starts an accession process that can last decades.
It will have to promise to join the Euro and abide by EU fiscal rules on budget deficits, if it can meet the criteria for membership. Scotland will have to rejoin the EU’s common fisheries policy and surrender control of its waters to Brussels.
Splitting Scotland from England, its biggest trade partner, after more than three centuries will be a nightmare, even without complicating factors such as Trident and North Sea oil.
It was hard enough to extricate the UK from 47 years of EU membership after a referendum that now risks spawning new independence votes in Scotland and Northern Ireland.
The price of Brexit freedom was new border frictions with the EU, the UK’s biggest trading partner.
Rejoining the EU won’t make up for the income Scotland loses in leaving the United Kingdom and its frictionless internal market.
Nicola Sturgeon insists she doesn’t want to repeat the mistakes of Brexit.
If she throws up barriers with the rest of the UK, she risks doing exactly that.