How Not to Pass a Carbon Tax

By Greg Mankiw

As long-time readers of this blog know, I have long advocated greater use of Pigovian taxes, such as taxes on carbon emissions. Such taxes can correct incentives by aligning private and social costs, and the revenue from such taxes can be used to reduce other, distortionary taxes.

Skeptics of Pigovian taxes on the right sometimes argue that such taxes are good in principle but in practice the left will co-opt them and, rather than using the revenue to reduce other taxes, will use it to fund ever larger government.

Sadly, that point of view is getting some support in Washington state.  The headline above from The Seattle Times reads 'Green' alliance opposes petition to tax carbon.  Why the opposition?  Because the ballot measure is revenue-neutral. Some environmentalists want to use the revenue from the proposed carbon tax to increase spending instead.

I believe that a carbon tax could someday win bipartisan support.  But before it does so, those on the left will need to convince those on the right that the tax would be a tax shift, not a tax increase.  The carbon tax needs to be evaluated on its own merits and should not be a stalking horse for a broader, big-government agenda.

Update: Responding to my post, John Whitehead writes, "The standard textbook treatment of a Pigouvian tax is agnostic on what happens to the revenue."

He is right, of course. So let me clarify. I was trying to make a point not about textbook economics but about practical politics.  Here are two propositions:

1. The tax system should be shifted in a Pigovian direction.
2. Government should be larger.

These are largely unrelated claims. Logically, one can believe both, neither, or only one of them.  In my view, it much easier to make the case to many voters, especially those on the right, for proposition 1 than for proposition 2.  As a result, if you strongly believe in proposition 1 and are trying to put together a coalition to make it happen, marrying it to proposition 2 is not the best move.