The politics of the election year are naturally the central focus of this Saturday’s Fabian new year conference ‘Causes to fight for.’

Labour faces a Conservative opposition which has conceded significant territory on ‘progressive’ policy issues while at the same time reinforcing its broad ideological hostility to state action. David Cameron’s progressive rhetorical shifts should be welcomed: that equality matters (though between the bottom and the middle); that health inequalities demand more resources for poorer areas; that the minimum wage, devolution and Labour’s international development work were good things which the Conservatives were wrong to oppose.

But the centrist Cameronism of 2006 and 2007 has retreated as the opposition has focused on its Thatcherite and anti-Keynesian opposition to the economic stimulus, proposing earlier as well as deeper spending cuts. The attempt to square the circle is made by the argument of ‘conservative means to progressive ends.’ The emphasis on austerity risks turning this into Thatcherite arguments while hoping for different results.

Labour’s argument should be the opposite: ‘Fairness doesn’t happen by chance’ – it depends on what governments do. And this must be fleshed out by concrete policy that can test the party’s political opponents, from defending universal services against a long-term retrenchment that will segregate the poor from everybody else, to ensuring that issues of a progressive redistribution of the tax burden are considered alongside the need for spending restraint.

In policy terms, the Conservatives place emphasis on an acceptance of Labour’s NHS spending increases (though most Conservatives are sceptical about what they see as a tactical accommodation), while asking for a doctor’s mandate for unspecified cuts everywhere else.

Labour exposed some vulnerabilities in the Conservatives’ under-prepared policy promises in the early new year skirmishes. Only by being more open about its own future spending plans in the March budget, however painful, will Labour open up what cutting faster and deeper entails.

Even as the election battle lines take shape, longer-term debates are beginning too. Saturday’s agenda will also reflect that this is a moment when the financial crash and the crisis of political trust will demand a broader rethinking of the politics of the left. From a new political economy which can create a sustainable ‘next capitalism’; working through how we win the public argument for a fairer and more equal society, major debates are opening up.

A significant theme will be the quest for a new pluralism. Must faith-based and secular perspectives be in tension with each other over the role of faith, or can they brought together to campaign for social justice? How could we change the culture of our politics to make it the norm to campaign across our party tribes on causes like climate change and tackle the far right?

The politics of the left needs to show not just that it has a clear electoral offer this spring but that it has the ideas, values and confidence to tackle the long-term challenges our society faces.