Soda tax is a tax on retail purchases of soda, whether from a store or from a restaurant. In the case of Berkeley, it would be one cent per ounce. In the case of San Francisco, it would be two cents per ounce. What's the key argument of each side? The key argument for the soda tax is that drinking sugar drinks is unhealthy behavior, and it not only has adverse effects on the people who drink them, but it also increases healthcare costs and reduces worker productivity. The main argument against is that it's a form of paternalism, and that people shouldn't be directed by government in making the choices they make, and they should be free to make their own choices. Is there a difference between the San Francisco and Berkeley soda tax measures? The San Francisco tax would be twice as high, two cents per ounce, whereas Berkeley would be one cent per ounce. The other major difference is that the San Francisco funds would be earmarked that is directed to particular spending on health, exercise, education, whereas the Berkeley measure, the funds would go into the general fund for spending on anything. Although in the case of Berkeley, they at least are planning to set up a board that would help direct the spending, but that's not a binding element of the measure. Have similar laws worked in the past? Well the big example we have is tobacco taxes, which have risen over the years and are now quite substantial as a share of the price of a pack of cigarettes. We know that in the last several decades we've had a big decline in smoking in the United States. Now not all of us just do the taxes that we've imposed. A lot of it probably has to do with education as well, but that taxes are certainly part of the portfolio of things that we can do to discourage engaging in unhealthy behavior and the soda tax is aimed at the same thing. What's important about this debate? We certainly have an increasing problem of obesity in the United States and the health problems related to obesity. There are many things that we might try to deal with this, including education about healthy eating and exercise, but certainly trying something like a soda tax is a good idea. Whether this particular soda tax is the right one, whether we might structure it differently by having it statewide, rather than at the local level, perhaps by having it larger, maybe by earmarking or directing the funds to particular uses. These are all questions one might ask, one of the nice things about having initiatives like this at the local level is that we can experiment. Different localities can pass different kinds of measures and we can see what works and what doesn't before enacting it at the national level.