[yummyfajitas]

There are two purposes to a sin tax: reducing consumption or compensating society for the loss caused by the sin. A perfect sin tax is set at such a level that no one needs to care which one occurs.

If a soda drinker inflicts $0.03 / soda on society, the perfect sin tax would also be $0.03. In such a regime, I don't care how much soda you drink since you are paying for your own health care via the sin tax.

[profgubler]

Yes, the externality is being paid for in that instance, which depending on your viewpoint is a good thing. But if that is the case that we only want to pay for your stupidity in drinking soda, than they shouldn't be pitching something that is for the health of the people, because it isn't.

Which brings us to the entire problem of a government run health care program. Anything deemed bad for us will be taxed and pitched as the fact that it is for the health of the people instead of to cover the costs of your choices on society.

And yes, I realize that a person who drinks a soda in a free market healthcare system still affects the cost of my insurance, however it is to a far less extent than when I am the one paying for my neighbors drink.