Let’s start with the economics. Substituting a carbon tax for some of our current taxes — on payroll, on investment, on businesses and on workers — is a no-brainer. Why tax good things when you can tax bad things, like emissions? The idea has support from economists across the political spectrum, from Arthur B. Laffer and N. Gregory Mankiw on the right to Peter Orszag and Joseph E. Stiglitz on the left. That’s because economists know that a carbon tax swap can reduce the economic drag created by our current tax system and increase long-run growth by nudging the economy away from consumption and borrowing and toward saving and investment.
Mitt Romney once supported this. Now he's just somebody that we used to know.