Martin Wolf on what's at stake in the battle over Britain's economic policy:

FT.com / Comment & analysis / Columnists - Martin Wolf: A map of the economic battleground: Unless fate intervenes, the next British general election will pit Gordon Brown against David Cameron.... [I]f Mr Cameron is to turn Labour vulnerability into defeat, he must also neutralise Mr Brown's strengths as a political philosopher and policy practitioner. This will not be easy. To succeed, he must focus not so much on ends as on means....

Mr Brown suggested three principles as guides to his politics: liberty, responsibility and fairness.* No Conservative could object to the first two. The interesting potential difference is over the last. Mr Brown argued that: "Fairness can be advanced by -- but cannot, in the end, be guaranteed by -- charities, however benevolent, by markets, however dynamic, or by individuals, however well meaning, but guaranteed only by enabling government."... The enabling state is a philosophical dividing line between intelligent left-of-centre and right-of-centre positions. This is, nevertheless, not as big a divide as enthusiasts would suggest on both sides. No party would be elected if it rejected the broad principles of publicly financed education and health, for all. Nor would any party win if it abandoned responsibility for infrastructure or for providing a safety net for the unfortunate. Contemporary politicians have to believe in an enabling state. In this respect, then, the dividing line between Labour under Mr Brown and the Tories under Mr Cameron is less sharp than both might wish. But they can still disagree over how -- and how far -- the state should enable. Fortunately for Mr Cameron, his side can now gain much more traction in this argument... the period of easy increases in public spending is now over... serious questions are being raised about the productivity of all this additional spending. As the Organisation for Economic Co-operation and Development noted in its recent survey of the UK, the evidence of declining productivity in the public sector, though highly uncertain, is disturbing.

How then should the Conservatives approach their task? They should start by admitting that the differences over aims between them and Mr Brown are not as large as enthusiasts on both sides proclaim. But the difference on means is highly significant.... The preliminary task remains for the Conservatives to re-establish a reputation for competence in macroeconomic management.... Mr Cameron's commitment this week to an independent Bank of England, independent assessment of the fiscal rules and independent provision of statistics goes in the right direction. This, however, is the easy part, since the consensus on macroeconomic policy is so strong. The dividing line is rather over how the state should deliver on the responsibilities it retains. Mr Brown's task is not to persuade people of Labour's aims, but of the workability of its means. Mr Cameron's is to persuade people that he has better ways of delivering similar aims. He has: they are called choice and competition. This is a question of substance. Let battle commence.