There are two beliefs that animate government R&D policy in the energy arena.

Belief #1: If you subsidize it, it will come. Wanting technology x to succeed in the market is a simple matter of throwing government money at technology x.

Belief #2: Politicians have every right to tell market actors what to invest in and what to buy. George Bush’s preferences for what Detroit ought to build (engines powered by hydrogen-powered fuel cells) and his preferences for what we ought to put in our fuel tanks in the meantime (200 proof grain alcohol, which goes by the moniker “ethanol”) should rule the day.

OK then, why not both subsidize the creation of — and mandate the production of — cars run by air? It’s doable. It’s carbon-free. And what possible environmental complaint might anyone have? Sure, it might be costly, and the car might not perform all that well, but government dough is like magic — all will be made right.