Tax does actually have to be taxing

In case you were in any doubt about the value of the Liberals, here they come with a plastic bag tax that isn't even a plastic bag tax. I'm objecting here not on the issue of whether we should have a plastic bag tax - I don't really see why not, but that's not the point - but the muddled and dangerous thinking behind the idea of a compulsory levy that doesn't go to government (as per the system in Wales). It's awful, in principle and in practice.

I think we can quickly attend to one half of the problem. Donating the money to a good cause is optional. Therefore, if they choose supermarkets can net additional profits by keeping the money. It's an odd (and badly designed) sin tax that incentivises those charging it to sell more. We wouldn't suggest that the markup on cigarettes was kept by the tobacco companies. Luckily, public and political pressure will mean that all the big firms will pass it on to charity. That's almost worse.

And there are two big reasons why:

• It suggests charity is a better use of money than government spending. It isn't: it's not universal; it's not monitored; it's not accountable and it's not capable of the large scale planning and investment that government does. I know we do it for gift aid, but that's for additional voluntary giving. This is compulsory. This matters: once you start attacking the principle that taxes go to government for government to allocate, it's not clear why you have government at all. 
• Worse, it also suggests a direct link link between a single tax and an area of spending. That's not what taxes are for (Nota Bene, people who bang on about 'road' tax). Fiscal policy is set to do two things: raise money (this won't) and influence behaviour (this will, pace tobacco). It's muddleheaded thinking to link this to spending priorities. That's just a waste of money simultaneously leading to a downward spiral of decay for poor places and unfashionable causes. Governments must allocate spending where we need it, not based on where they raise it. 

In the end this particular element doesn't matter very much, and not just because it's a Liberal policy. It's not pointless (it will shift behaviour in probably a positive way); it's not very much money (especially if it works). It's just an unnecessary signal in the wrong direction and symptomatic of the weakness of political thought. 

Anathema.