There are two questions in voters' minds about taxes. One is "How much will I have to pay?". The other is "Since we have to pay taxes, can they be made less bad?" Most voters will, when they think about it, accept the possibility of paying a little more for the time being in order to get less bad taxes overall. That is what Ming is offering. It has the feel of a potential vote winner.

What voters hate is being singled out to pay more than other people. The art of presenting tax proposals is not being pinned down to identifying the losers; and the art of attacking them is to identfy losers. Since the truth is that it will need months of work in Government on the details of any major tax change before the effects on individuals can be reliably estimated, the honest and viable presentation is "I don't know whether you or I will come out of this better off or worse off. What I am sure of is that on average we will all be better off."  

Presenting these proposals needs time. We have time. Lets use it effectively.

Menzies Campbell's taxation vision as outlined at a Centreforum event last week is radical and coherent. It is a grown up approach to policy which provides a clear answer to those opponents who lazily accuse the Lib Dems of lack of clarity. But the question must remain whether it is a vote winner. The honesty of the position about tax increases as weill as cuts is admirable. But will people remember the eyecatching cut in income tax or note the tax rises? For the moment, it has done little to neutralise the hefty impact of a move to local income tax on middle earners, a chief weapon of Lib Dem opponents.

I should declare an interest - I am a Labour party member so I am not too worried about Lib Dem policy being or not being a vote loser. (Having said that I don't want the Tories to hoover up Lib Dem seats in 2009.)

What is the role of the Lib Dems? Do they aspire to leading a government after the next election? On the other hand do want to shape policy discussion (perhaps even lead debate in some areas)?

Historically the Liberals have played a vital role in promoting serious and thoughtful policy discussion - over Europe, constitutional reform, etc. Sadly a clumsy populism in recent years on local government finance and funding education has meant that Lib Dems have offered little.

Hopefully the Lib Dems will adopt the redistributive and green proposals that have been put forward - and raise the quality of debate on this vital issue.

ps The FT on Tuesday carried an interesting (and positive) op-ed on the Lib Dems and tax by Samuel Brittan.