Well, first of all, I would endorse Kevin's comment. It's a question of what you do with the revenues in terms of some of the offsets. You are correct, also, to lay out that, as we've seen with ethanol, when you make major changes in policies, it could have impacts on prices and all sorts of things, and we need to understand that.
With respect to my comment about restructuring the federal fuel excise tax, it's already an existing tax, and you can restructure it in all sorts of different ways, including, for example, reducing the gas tax to let's say 5¢, and then bringing in a broad-based environmental tax that would apply to natural gas and coal products as well as other petroleum products that are not subject to the environmental tax.
I've calculated, in the case of a carbon tax, that if you have a 5¢ tax on gasoline--so you're cutting the gas tax by 5¢ and then applying the carbon equivalent--in effect the federal government would actually still raise about $2 billion to $3 billion. Of course it also means that you have a much smaller tax, and of course the ramifications of that in trying to deal with all the offsets and some of the issues are much less. It also gives you an opportunity to see how the tax operates, because I don't think any of these tax reform proposals should ever be brought in such that you have huge changes at one time. We have to see how they work, how they impact on the economy, including prices that are going to be affecting people.