I agree that taxation on expenditure is regressive in nature, and can therefore mainly be justified only as a disincentive to a form of expenditure.

However, if you concentrate solely on income taxation, there will need to be some form of capital taxation too, and then liquidity issues arise.

Fishing has to reduce, or there will soon be no fish left (big in the papers last week) - the obvious alternative being the general reduction in population - but the CFP is also a price stabilitation regime, I think, so better to reform it than remove it. Price stabilisation regimes need to be very carefully thought through or they result in wasteful production for subsidy followed by destruction of the product - like the grain mountain and the wine lake.

IMHO travel costs should be capable of being offset against income not only in relation to business travel as such but also to get to work and seek work -up to limits (by fuel efficiency, pollution etc) and up to certain limits. My late wife and I used to drive 40 miles each in opposite directions to work, and it is better for mankind to reduce such waste and damage.

But can you really say any of these are the single most important issue?

Maybe Malthus had it right, and a few good infantry-intensive wars, maybe halving the world population, would solve quite a few problems at a stroke? How about another American civil war (although I don't know how we might start it)? How about a new Black Death (perhaps someone beat me to the idea and designed Aids for the purpose already, but if they want to solve world problems they released it in the wrong place...)

But seriously folks...

What about immigration? I know of a trade union branch espousing the absolute right of all to immigrate to England for political or economic or any other purpose - but that can't be sensible. I know of others who say "no deprivation of liberty without fair and public trial" - but again some executive power is in practice essential, and the real issue is how to ensure it is properly limited.

How about legal aid? No right is of value unless it can be enforced, and if only the rich can afford lawyers only the rich have effective rights.

What about unions - the courts have just held that the right to join a union as such is a right protected by Human Rights law - but that rights negotiated by a union are not, the consequence being that the ability of labour to organise can be (and is being) reduced to a paper moon, an illusion with no real substance (with the consequence being that organised capital can and will then deprive workers of the fruits of their labour)? France has started on the road back to wage slavery...

What about the famous whore of the middle classes - Laura Norder? If property is legitimate (a distinct from property being theft) then if the rule of law is not enforced society wholly breaks down. But how do we ensure that the law is neutral between members of society, and not the weapon of one sector of society against another.

Really must go and do something useful now....