The strategy that's most likely to keep the UK together

Such rhetoric naturally elicits rebuttals from the SNP and others, pointing out their obvious inaccuracy. The SNP holds a minority of seats at Holyrood and has done for 11 of the nearly 16 years they’ve been in power.

Mark McGeoghegan: The SNP needs a broader strategy to make a de facto referendum work

It has outright control of just one of Scotland’s 32 councils, despite achieving the highest share of first preferences in local elections since the change to the Single Transferable Vote.

The SNP exercises surprisingly little unilateral power in Scotland, given its political dominance. Where it does wield power, it tends to do so with the support of smaller parties. And, as ever, it wields that power courtesy of the Scottish voters.

The question, then, is why have we seen this growth in hardline rhetoric? The obvious answer is that the more hardline wing of the pro-Union coalition has become more prominent since the referendum, as have their ideas.

We often characterise Scottish politics, particularly constitutional politics, as static – as if nothing ever changes. But that isn’t true. Since the 2014 referendum, the No lead has shrunk from 10.6 points to an average of 0.36 points across 2022’s polls. The last time No held an annual average lead of more than one point was in 2019.

Scotland’s position in the Union would be on a knife edge if a referendum were held. While one currently seems unlikely to happen, that may not always be the case – if the next election results in a hung Parliament, with the SNP capable of putting Labour in government, a referendum would be their price.

In the past, Scottish unionism was characterised by the argument for a multi-national state – despite the nations of the UK being different bodies politic, they hold in common sufficient interests and preferences to legitimise a shared state.

This argument supports a union state rather than a unitary state, as Michael Keating, professor of Scottish politics at Aberdeen University, puts it. The recent critical shift in the pro-Union coalition has been away from support for the union state towards support for a unitary state.

This newly prominent position refuses to recognise national diversity and instead sees the British state as a traditional nation-state for the British nation. It is not unionism but British nationalism. The crucial faultline in the pro-Union coalition now is between traditional unionists, today dominated by devolutionism, and British nationalism.

The two entail different strategic approaches to maintaining the Union, and which comes out on top in the coming years could have decisive consequences for Scotland’s constitutional future.

The devolutionist strategy allows national differences in policymaking within the UK in the belief this will dampen the desire for secession. It is epitomised by the post-referendum Smith Commission and associated reforms to the Scotland Act, giving the Scottish Parliament greater powers over taxation and a range of other areas.

The British nationalist strategy is opposed to such accommodationism. Rather than accommodating national differences, they seek to restore greater power to a more assertive Westminster.

For example, the Sunak Government is considering various options to intervene in the Scottish Parliament’s Gender Recognition Reform Bill, from blocking the bill through a Section 35 order to challenging it in the Supreme Court.

A Section 35 order would symbolise British nationalists’ desire to start rolling back the autonomy of the Scottish Parliament and Scottish Government. Devolutionists would argue that such a constitutional rammy would boost support for independence.

Their British nationalist counterparts would retort by pointing to two decades of devolution as providing the grounds on which Scottish secessionism has reached its current strength. They argue that only disempowering the devolved institutions can prevent the SNP from using devolved powers to “stoke nationalist grievance”.

We have no counter-example of a Scotland in which the Scottish Parliament never reconvened, so we cannot say with any degree of certainty whether or not accommodationism exacerbates Scottish secessionism.

However, we can look at the success of counter-secessionist strategies pursued worldwide. Research by Dawn Brancati at Yale University suggests that devolution can effectively dampen secessionism but simultaneously empower secessionist parties through devolved institutions.

Likewise, the work of political scientists Emanuele Massetti and Arjan Schakel shows that devolution can radicalise regional parties, making secessionist claims more likely, but not necessarily secession itself.

Mark McGeoghegan: Scottish independence is a battle for hearts, not minds

And recent research by Micha Germann and Nicholas Sambanis suggests that the opposite – undermining or removing the autonomy of sub-state nations – can inflame secessionist tensions and escalate such political conflicts. In some ways, both Scotland’s devolutionists and British nationalists are right. Devolution can empower and encourage secessionist political parties and movements, but also make secession less likely.

The strategic debate in the pro-Union camp will not be resolved based on which strategy is more effective. After the next election, a Conservative government would continue to be pressured by its British nationalist wing to act more assertively in Scotland. A Labour government would likely pursue a soft accommodationist strategy in the vein of Gordon Brown’s proposals to overhaul the constitution.

But I think it is clear which strategy is more likely to keep Scotland in the Union. It may empower the SNP, encourage secessionist claim-making, and infuriate many Unionists, but accommodationism has a track record of holding multi-national states together.

Unionists should keep that in mind – imperfect as they are, Gordon Brown’s constitutional proposals may be their best option for now.