Despite voter concern about immigration falling to its lowest level in nine years, immigration is back as both political box office and political football.

The escalating problem of irregular migration from the Arab spring is reopening old arguments over "burden-sharing" in Europe, which Nick Clegg was dragged into on Tuesday. Back home David Cameron, having gone quiet on immigration over the winter, returned to the issue aggressively during the local elections.

Conservatives have often banged the immigration drum during a campaign, only to put it away once its job is done. But this time Cameron is likely to keep up the focus, taking a risk on a bit more Lib Dem unhappiness, in order to enjoy an ongoing political dividend.

The manner in which sensitive proposals on restricting family and marriage visas were trailed on Monday looks like an early sign of the tactics urged on Cameron by Tim Montgomerie (following Tony Blair and Margaret Thatcher) of picking "big, defining fights on popular projects" such as immigration as the best way of avoiding his agenda being defined entirely by the spending cuts.

It also offers an ideal sop to the Conservative right, along with continuing to yoke the immigration cap to welfare reform – two of the Tory right's favourite coalition policies.

Labour, meanwhile, knows it can't avoid immigration for ever, and a bolder approach now could begin to detoxify the issue for it, tackling continued resentment among southern voters over Labour's record. Ed Miliband's wider strategy on the "squeezed middle" and the Blue Labour agenda provide him with new ways of talking about immigration that are more constructive than just saying, "Sorry, we let too many in."

Underneath the tactical manoeuvring, there is actually less polarisation in the two main parties' broad strategy on immigration than in previous years. In the four decades to the 2005 election, Labour was seen as basically pro-immigration, Conservatives basically anti. Since then, both have tried to shed those old images, and are competing to be identified with the centre ground: roughly, pro-immigration-but-less-of-it, a more balanced approach that is now routinely applied to the social and cultural as well as the economic aspects of immigration. Ed Miliband is continuing on these lines, and it must remain Cameron's preferred strategy, too – as well as his best chance of preserving coalition unity.

There are three main battlegrounds in the campaign to win the centre: overall numbers, the economy and culture. On the numbers, both parties have flagship policies with the same basic objective: more quality, less quantity. Labour's version, the points-based system, is more realistic about the nature of migration flows, the workings of the immigration system and the needs of the economy. In contrast, the Tories' cap is crude but easy to explain, and on an issue where trust has disappeared, this has so far proved decisive.

On the economy, Labour needs to win the argument again about immigration's contribution to overall growth and extend that argument to reducing the deficit. The pro-immigration line on the economy had a damaging air of complacency in recent years, but the evidence remains basically sound. The more radical debate is over the role of immigration in the complex dynamic at the lower end of the labour market.

Cameron's argument here is that if we reduce immigration while at the same time making it harder to live on benefits, this will shift large numbers of people from welfare to work. Miliband's argument, though less clearly put, seems to be that if wages and conditions improve, the result will be simultaneously to reduce the demand for low-paid migrants (at present the only ones willing to do some of these jobs) and to shift people from welfare to work, but by making work more attractive, rather than making living on benefits harder. Both arguments present low-skill immigration as a symptom of our real problems – welfare for the Tories, wage stagnation for Labour – rather than the cause.

On the final battleground of culture, the target is the voters identified in the recent Fear and Hope report as neither relaxed about immigration nor implacably opposed to it. For Miliband, the emergence of Blue Labour will help him keep his party's debate focused on this centre ground.

The Conservatives have a headstart here, but this could be undermined by two factors pushing them towards a more polarised position: the neocon approach of Michael Gove and others – evident in the more confrontational passages of Cameron's Munich speech – and the desire to perpetuate anger against Labour by talking up the problems of integration, rather than doing anything to solve them.

On all three battlegrounds – numbers, the economy and culture – narrative will be more important than policy or statistics. The Tories start with a clear advantage, but their narrative may become increasingly frayed by coalition dynamics, the realities of government, and an inability to control their instincts tugging them off to the right. Labour meanwhile has the makings of an alternative story, but it is a long way from being fully fleshed out.

All in all, the debate might be more interesting over the coming year than the cynics think.

Matt Cavanagh is associate director at IPPR.