I'm not sure exactly what I think about Dave Roberts' argument that the political downsides of a gas tax vastly outweigh the substantive upsides. It's worth saying, up front, that I think a straight gas tax is vanishingly unlikely, and so it hardly matters. But even so: The idea that even a fairly heavy tax on gasoline wouldn't produce the behavioral changes we're looking for seems fairly consistent with the evidence. It tends to be the case that the strongest advocates of gas taxes are urban dwellers, and their lives -- things are close together, transit options abound -- create an availability bias that implies driving is a choice, when for most folks who drive, it's far closer to a necessity. Of course, the idea behind a gas tax is that the new revenue funds a new transportation infrastructure, so advocates are not exactly ignoring the need to build. And there's no doubt that market signals are powerful. But I think there's fair concern over whether they're enough. The next issue of The American Prospect will feature a Nordhaus and Shellenberger piece arguing that liberals have locked themselves into a peculiarly conservative frame in which they presume that the swift deployment of market forces can provide a proportional response to the dangers of carbon emissions, when in fact this is the sort of national threat that calls for a heavier dose of central planning and coordinated efforts. That may mean sacrificing some efficiency in order to get more action, but they argue it's worth it. As I said above, I'm not sure where I fall on all this, and it's not clear that investment is in tension with pricing, but as someone versed in the history of health reform, it's not hard to imagine a scenario in which the environmental movement launches a massive campaign for a gas tax or carbon pricing that ends in total failure, and five years later everyone wishes they had seized the moment to fight for huge investment expenditures instead. What Roberts is arguing, in effect, is that the harder thing might well not be better here, and if he's right, thats an important and unintuitive point.
