In a keynote speech at the end of last year, Deputy First Minister Nicola Sturgeon declared the United Kingdom constitutionally “unreconstructable”. Only complete political separation from Westminster, she argued, could deliver the control over areas such as tax and welfare polls consistently suggest most Scots want. Of course, this claim doesn’t really stack up: in recent months, each of the three main unionist parties has announced, albeit reluctantly, that they will seek significant new powers for the Scottish Parliament in the event Scots vote against independence in 2014.

Replace ‘the constitution’ with ‘defence and foreign affairs’, however, and Sturgeon’s assertion becomes much more plausible. This week, the UK Coalition Government revealed how it intends to spend a £160bn defence equipment budget over the course of the next decade. Its plans include the purchase, at the cost of £35.8bn, of seven new Astute class attack submarines and a fleet of nuclear-armed Vanguard submarines. A range of new military aircraft and unmanned drones, valued at £18.5bn, also feature on the MoD’s shopping list. Although, overall, UK defence expenditure is forecast to be lower in 2015 than it was in 2010 (the Tories still have a deficit to reduce), these purchases will be funded by an above inflation rise in spending on military armaments after the next UK general election. Reports suggest extra cash will be made available through additional cuts to the welfare department.

The proposals were laid out shortly after David Cameron jetted off to Algeria and Libya to address the growing threat posed to UK interests by Islamist terrorism in North Africa. In a speech in Algiers, Cameron said Britain was prepared to use “everything at its disposal” to defeat Al-Qaeda in the Maghreb, a pledge he partially fulfilled with the deployment of 40 British ‘military advisers’ to conflict-hit Mali and a further 200 British troops to neighbouring African countries to help train the Malian army. Much of the rhetoric Cameron used on his trip echoed the language employed by Tony Blair during the ‘War on Terror’. For instance, at one stage, Cameron described the recent Algerian hostage crisis as a “reminder that what happens in other countries affects us at home”. This deceptively banal phrase could, in fact, have been lifted straight from the liberal interventionists’ handbook (see Blair’s 1999 ‘Chicago speech’).

These developments are of particular significance to the Scottish constitutional debate because they indicate the likely trajectory of UK government defence and foreign policies in the years to come. Left-leaning and progressive unionists may have hoped the passing of the Blair era would mark the end of Britain’s attempts to rescue, by force if necessary, its status as a first-rank global power. No such luck: the current generation of Conservative leaders seem every bit as keen to preserve what remains of British imperial prestige as their New Labour predecessors. Indeed, New Labour’s militarist tendencies live on in the careers of Scottish-unionist politicians Jim Murphy (Shadow Defence Secretary) and Douglas Alexander (Shadow Foreign Secretary), both of whom regularly cite the size of the British defence budget – the fourth largest in the world as a proportion of GDP – as a reason in itself for Scots to reject ‘separation’.

One of the current ironies of Scottish politics is the way public opinion divides on the question of ‘more powers’. As noted above, most surveys show widespread support for the devolution of economic and social matters to Holyrood. Yet, when it comes to Scotland’s role in international affairs and the scope and capacity of its military, Scots continue to prefer London rule to Edinburgh rule. The irony lies in the fact that the case for distinct Scottish defence and foreign policies is, if anything, clearer than the case for a distinct Scottish economic policy, which tends to rest on highly technical arguments about the sustainability of North Sea oil production.

The ideological dividing lines are clearer in this regard, too. The SNP and the Greens, together with the rest of the pro-independence coalition, want to radically reduce Scottish military expenditure and re-invest the savings in more socially productive industries. Conversely, the unionist parties (with the possible exception of the Liberal Democrats) deliberately and systematically blur their defence and industrial strategies in an effort to persuade Scottish shipyard workers that their jobs depend on UK government contracts.

At the moment, it seems unlikely Scotland will vote to leave the UK in 2014. The Yes campaign has tried a range of tactics – including, of course, relentlessly accentuating the positive benefits of self-government – to shift support for independence towards the 50 per cent threshold. They haven’t worked. Similarly, the latest plan advanced by Nicola Sturgeon, to portray the British constitutional system as utterly inflexible and beyond reform, looks set to fail. Perhaps a new message focused on the UK’s refusal to accept its diminished global status – and adjust its spending commitments accordingly – would yield better results.