The usually insightful Becker-Posner duo have just added another debate on environment and national security. Gary Backer started by saying that environmental protection and national security goals may well coincide, particularly when carbon taxes and nuclear plants are involved. Richard Posner essentially agrees with him on the main points. This is rather good news, since a carbon tax would indeed go a long way towards both goals—weaning us off oil for environmental and national security reasons.

Unfortunately, the current practice in Washington is not quite as clear as professorial policy discussions: talk of energy independence often muddles the issues and may lead to a self-defeating policy mess. As a result, these harmonic goals may start to diverge again.  The US corn-based ethanol industry, for example, probably has a net negative impact on the environment, since it requires so much energy (and land, and petroleum-based fertiliser) to grow and process the corn.  Yet congress continues to make corn-based ethanol the cornerstone of US renewal policy, to the point that voracious demand from biofuel processors has started to push up corn prices on the world market.  One might defend this on the grounds that it makes more sense from an energy-independence standpoint—but not too easily, since better alternatives like carbon taxes could kill two birds with one stone.