If ecigs are less harmful by orders of magnitude than tobacco, then substitution away from tobacco is a good thing.
1. Tobacco companies pay money to the government for socialized tobacco health costs.
2. Ecigs don’t do the same.
3. Ecigs have a much lower health cost.
4. Private tobacco health costs are a choice and ought not be a matter of public policy.
5. If Ecigs lower socialized tobacco health costs (through substitution) by an order greater than the tax revenue collected, then ecigs are a net plus for the balance sheet of government (And maybe a net minus in political power by removing a carrot).
6. Government employees interested in the balance sheet have an incentive to support ecigs. Government employees interested in political power have an incentive to oppose ecigs.