Today saw a great speech from Nick Clegg at the Lib Dem conference, arguing for tax cuts for low and middle income earners to help meet rising food and fuel costs. The left don't like this because it doesn't involve veneration of the state, and the right don't because they focus their occasional tax cutting efforts at the better off - which is not to suggest that they cut taxes overall in the long run.
The left shouldn't object of course, because they should recognise that fuel and particularly food are even more basic and important than public services like ID cards and wars. But now I want to address why the right shouldn't object either, because this policy will benefit the rich too in the long run.
According to trickle-up economics, what happens when the low and middle income earners have more money in their pockets is that they go out and buy more of the things they need, so that money eventually gets recycled into executive bonuses, dividends, and so forth. So tax cuts for the poor benefit us all in the long run.
Now it should be said that not everybody agrees with trickle-up theory. Some argue that it is just spin for the doctrine that what is good for the poor is good for the country, a doctrine that should be resisted because, er, they aren't poor, or something.
But seriously, "supply siders" argue for cuts in taxation on profits to encourage investment. But as post-tax profits drive investment, these can also be boosted by boosting pre-tax profits, by leaving ordinary people with more in their pockets to spend. The difference is who gets the direct benefit and who merely gets trickled on, er, or trickled under.