I think there is something to what you say. Let me try to defend it this way. The question is how broad a target you're trying to hit. When you try to have a credit for something that is very narrow, you create the incentive to shift things around and you have the difficulty of defining what's in and what's out.
So my preference in greater environmental taxation would be having a very broad base for environmental taxation. As Professor Mintz mentioned, something that is very broad-based, that is neutral across jurisdictions, would be the best way to go.