“We are all minorities now,” declared Jeremy Thorpe after the inconclusive general election of February 1974. The Liberal Democrats under Nick Clegg enjoy a poll rating comparable to that achieved by Mr Thorpe. At the time this figure was seen as a breakthrough. Now there is a sense that the Lib Dems remain stubbornly ensconced as a minority, while the other parties enjoy alternating large majorities. Mr Clegg's leadership is not regarded as providing a way out.

That is to do Mr Clegg an injustice. He is streamlining his party's organisation. And he has enunciated the party's principal aim as doubling its parliamentary strength - an ambitious target, but less so than the grandiloquent fiction, beloved of his predecessors, of aiming to be a party of government. This more modest objective also sets the Lib Dems free. Their programme does not have to be one for a putative Cabinet to implement. They can be bolder, acting as a ginger group, helping to change the political debate and championing new ideas.

Yesterday Mr Clegg, who has already made a useful contribution to the national argument on school choice, gave a further indication of how he might use this new freedom. He signalled that the party would seek to cut taxes overall, and declared that the “era of big, wasteful, instrusive government” was at an end.

Mr Clegg's stance was a lot longer on intentions than specific economies. But it is no mere shift of emphasis that the Lib Dems will seek to return money to taxpayers rather than spend it on social programmes. This is a significant change.

In the early Thatcher years, the Liberal-SDP Alliance's programme was scarcely distinguishable from the high-tax and high-spending lineage of old Labour. In the 1990s, the Lib Dems positioned themselves as a partner in an anti-Conservative coalition. In this decade, the party has been perceived, on tuition fees and taxation (as well as foreign policy), as to the left of Labour. Now the Lib Dems are striking out in an altogether different direction.

The implict message of Mr Clegg's speech is of an interesting attempt to resolve the party's continuing search for identity. Instead of moving right to win Conservative votes, or moving left to win Labour seats, Mr Clegg is moving right hoping to attract Conservative votes in Labour seats. This may prove a difficult task given current polls but is the political logic of an appeal to cut the tax burden.

Mr Clegg's tax-cutting message raises many questions. It is unlikely to be realisable in anything but the long term, nor would it be easy to relieve the financial pressures on low-income households as the party envisages. A reduction in the basic rate of tax from 20 per cent to 16 per cent would be a significant boost for middle-earners; it would scarcely touch the lowest-paid, who would in addition be disadvantaged by “green” taxes.

Replacing council tax with a local income tax would be of particular benefit not to the low-income households but to pensioners living in large houses. Whatever Mr Clegg desires, for many voters his policies will mean tax rises, and quite large ones.

In addition, the Lib Dems' pledge to find £20 billion of efficiency savings is disappointingly tame, lacking so much detail as to verge on the ridiculous. And the pledge to reduce the number of MPs by a third is a populist proposal but probably simultaneously wrong and beside the point. Nevertheless, Mr Clegg has done his party and public policy a service. He has shifted the balance of political debate towards lower taxes and lower spending. That is a debate that ought to be taking place.