Why does she bother? Nicola Sturgeon has had precious little support from the Scottish press for her efforts to defend the powers of the Scottish parliament against Brexit.

Most voters seem unmoved even if they understand the constitutional arguments. And many SNP supporters, who never believed in devolution anyway, wonder why she's invested so much political capital in what is essentially a unionist project. Even the Welsh have thrown in the towel and accepted that Westminster can impose direct rule over Cardiff, so long as it promises to stop doing it in seven years time.

She seems to be fighting a lone battle, but there is surely something rather admirable in the First Minister’s determination to hold the line. For this has nothing to do with promoting “Sturgeon's nationalist agenda”, as mother-to-be Tory leader, Ruth Davidson, insisted last week: the issue is devolution not independence. The First Minister is defending the principle of consent that underpinned Donald Dewar's 1998 Scotland Act. You could equally say that it's odd for a nationalist to strengthen the Union by trying to save devolution.

But for Nicola Sturgeon, this about fairness and not treating Scotland with contempt. You could tell from her tone of voice at First Minister's Questions on Thursday, that she felt personally affronted by the supposed “final compromise” offered by the UK government. The proposed amendment to the objectionable Clause 11 of the EU Withdrawal bill said that Westminster would always seek Holyrood's consent before it legislated in devolved areas like environment or agriculture, in line with the Sewel convention. But it goes on to define consent as happening when Holyrood “does not agree” and even when it “refuses consent”.

The Scottish lawyer, Johnathan Mitchell QC called this “the rapist's theory of consent: (a) Yes is consent, (b) Silence is consent, (c) No is consent”. Perhaps it's because Sturgeon is a feminist and believes that consent should mean what it says. Who in their right minds would accept such an abuse of language? I am genuinely mystified that this draft amendment was not plastered across the front pages of every Scottish newspaper last week. Instead the line was “Sturgeon isolated” as talks break down and Lord Hope was wheeled out to insist that consent had somehow been offered when it hadn’t.

We're told that this centralist diktat is necessary to create coherence in the “UK internal market” after Brexit. If Holyrood doesn't give up its right to have a say on the use of chlorinated chickens or GM crops, then all hell will break loose. Trade within the UK will cease. Britain itself will be brought to its knees. Yet, there is no reason why the principle of consent, or power-sharing, which underpins the workings of the European Union and the Good Friday Agreement in Northern Ireland should not continue to apply in the UK. The press comment has all been about Nicola Sturgeon's intransigence and “dogmatism”. Yet the UK government could resolve this tomorrow simply by recognising the devolution status quo. Yes, the UK government would have to argue its case in future, but is that such a bad thing?

The Smith Commission in 2015 promised that the Sewel Convention would be placed on a statutory basis. This never happened. The EU Withdrawal Bill goes the other way entirely by effectively repealing the 1998 Scotland Act. That landmark legislation secured a significant degree of sovereignty, of autonomy, for the Scottish parliament by confining Westminster’s reserved powers to those in Schedule 5, namely defence, foreign affairs, currency etc. Everything else was assumed to be a responsibility of the Scottish parliament. Few realised at the time quite how radical Donald Dewar’s bill was, but it in effect created a quasi-federal UK. The Scottish parliament was just not given powers on loan from Westminster, but possessed and exercised them as of right. This made the difference between a unit of local government, which exercises powers handed down from above, and a proper parliament, which exercises a degree of sovereignty.

To some, this sounds like “pointy-headed” constitutional verbiage, and the UK government claims not to recognise it. Conservatives never bought into devolution anyway, and are happy to see a unitary British state restored. But this autonomy was central to the devolution settlement. It was why Holyrood was able to forge ahead with legislation like the 2005 smoking ban without worrying about being over-ruled by a Westminster government that opposed it. Pesticides, food labelling, animal welfare, even fracking are among the powers Westminster wishes now to seize. No one denies that these are responsibilities of Holyrood, even if they had to be in accordance with EU law. Westminster legislation also had to be compliant with Brussels before Brexit.

The Prime Minister says that the power grab is only a temporary measure, lasting for seven years, and after that the powers “will be handed back”. But by then the matter will have been resolved by precedent. Holyrood, it will have been demonstrated, does not exercise powers in its own right, but only under loan from Westminster. It will become what Billy Connolly always said it was: a “pretendy parliament” - a plaything. The real power will lie elsewhere.

This is what true nationalists have always believed. Before Alex Salmond became leader, the SNP opposed any devolved parliament on the grounds that it was a colonial ploy: a ruse to fool the natives into thinking they ran their own affairs. As Enoch Powell famously said, “power devolved is power retained”. This remark was very much in Donald Dewar's mind at the time the Scotland Act was drafted, not least because Alex Salmond, then SNP leader, never let him forget it. Dewar wanted to show that a Scottish parliament, within the Union, could be more than just a pretence, and could exercise true autonomy, in home affairs at least.

But these arguments seem to have faded with time. It seems that even many in the Labour Party, given their silence on the issue last week, no longer believe in the parliament their own government created. They have inadvertently taken on the SNP's old narrative, that the only choice for Scotland is between independence and a unitary British state. Perhaps many would be happier going back to the days when Labour dominated the old Strathclyde Region, which was a unit of local government that didn't have any pretensions to power but had the gift of patronage.

Yet, as this paper explained two weeks ago, the Scottish Labour leader Richard Leonard, is supposed to be a supporter of federalism – a system of shared sovereignty. That is what is at issue today. Under any federal system, it would be an abomination for Westminster to simply impose consent on a state government in areas where it has a clear legislative responsibility.

But many nationalists will be more than content to have done once and for all with devolution, federalism and half way houses. Many never rated the Scottish parliament and are rather pleased to see their suspicions confirmed. Next time there is a referendum on independence, or even the threat of one, SNP stalwarts will say: just remember the 2018 Consent Clause – the rapist's charter for government.