It will be a momentous day when Britain does finally make a decision about its membership of the European Union. With David Cameron about to promise a referendum that includes the prospect of the UK leaving, the debate begins immediately – even if the Prime Minister doesn’t envisage the poll taking place until well into the next parliament.

As I wrote in this week’s magazine [2], Labour’s policy is currently not to match Cameron’s pledge straight away. That doesn’t mean Ed Miliband won’t get bounced into having a referendum in his manifesto by 2015. Even those in the shadow cabinet who argue against what they see as an irresponsible toying with the UK’s diplomatic and economic fortunes admit it would be a challenge to get through an election campaign without a referendum offer when the Tories are gleefully touting theirs. (The same goes for the Lib Dems, who had a referendum - in the event of significant EU changes - buried deep in their 2010 manifesto.)

So the next two years will be thick with European argument. Thick, but not necessarily rich. By that I mean, judging by the standards of recent political debate, we can expect rhetorical chicanery and wilful obfuscation to trump evidence and rational analysis.

To illustrate the point, I found myself considering how the European issue – obviously a matter of paramount significance to the nation – fits into the great intellectual frameworks that the two main party leaders have set themselves. That is, on the Conservative side, “The Global Race” and on the Labour side “One Nation”. Cameron crowbars the global race into every public pronouncement and parliamentary answer he gives. He got at least four "global races" into last week's press conference launching the coalition's mid-term review. The essential point is that Britain must be made competitive in a scary global world and that requires lean finances, education reforms, low taxes, deregulation and maybe a spot of strategic investment in snazzy up-and-coming industries. It is Cameron’s big thing, or rather his biggest thing since the Big Society, which turned out to be a small thing. Or no thing at all.

Miliband, meanwhile, conceives One Nation Labour as the answer to the question ‘what comes after New Labour if it is not to be a return to Old Labour?’ It is all about solidarity and harnessing a spirit of patriotic national renewal to re-imagine what government can do and how it can serve citizens at a time of austerity. (He has a speech on this very subject today, trailed in this morning's Guardian [3]. There's a more detailed, albeit mildly fawning preview here [4].)

The new rule in Labour policy making is that any new announcement or initiative has to have a plausible One Nation rubric. The equivalent rule on the Conservative side is that a measure or policy should boost Britain’s chances in the Global Race. So these are the two competing, over-arching themes governing Labour and Tory thinking at the highest level; the Narrative, as political strategists like to say. Presumably then, they clarify where those parties stand on the vital question of Britain’s relationship with the European Union.

Let’s start with the Global Race. This should be easy enough. Britain needs to compete with rising Asian powerhouse economies but it is shackled to the rotting corpse of continental states, bloated on welfare and overrun with unemployed youths, underskilled and without prospects because rigid labour protections lock them out of the jobs market. So to compete in the global race, we must break free from the EU.

Or, the future of trade, commerce and the global economy lies in the relationship between great continental power blocs. China doesn’t care about the UK the way it cares about the US or Brazil. But it does care about the European single market and if London doesn’t have a say in how that system operates and what the terms of trade are, we will be an isolated and desolate outpost starved of investment and influence. So to compete in the Global Race we must by at the very heart of the EU. Hmm.

What about One Nation? Well, at first sight, putting national solidarity at the heart of policy might suggest qualms about the notorious surrender of sovereignty associated with membership of the EU. So perhaps a One Nation Europe policy would support repatriation of powers from Brussels.

Although, there is an argument that says a powerful voice in the EU – and the social protections that European institutions guarantee – is our best bulwark against the corrosive forces of unfettered free market capitalism that hollow out communities and lead to a race to the bottom in workers' rights. So a One Nation European policy is actually pro-EU because it wants Britain to be a progressive place that looks much more part of the social market/social democratic traditions of the continent than the neo-liberal, individualistic free-for-all culture of the US.

Of course you can play this game with pretty much any policy and any slogan. The point isn’t that the Global Race and One Nation are vacuous phrases – as concepts they have great potential to illuminate all kinds of debates in British politics. But I have a feeling that they won’t. I’m pretty confident that when David Cameron and Ed Miliband set out their European positions in the next few weeks, the former will be all about the Global Race and the latter will be about One Nation. I’m also confident we won’t be any closer to knowing what either of them really means.