The announcement took place at the Clinton Global Initiative in New York, and the former president called it “huge.” (What’s huge, as nutritionist and public health expert Marion Nestle points out, is that “soda companies are at last admitting their role in obesity.”) Clinton might have noticed that a not-especially-aggressive tax like that in Mexico may have taken half of that 20 percent bite in just one year. The difference is that a well-thought-out soda tax reduces consumption and also industry profit, while contributing to a larger anti-junk-food campaign. And it doesn’t rely on the word of the profiteers to succeed.

Which brings us back to the Bay Area. The San Francisco measure is a much more aggressive one, the kind I (and many public health advocates) would like to see: a two-cents-per-ounce tax (that’s 24 cents per can, which experts believe to be significant; plus it sounds significant) with the resulting money (estimated to be a minimum of $30 million) being channeled into health and wellness programs. That second feature, good as it sounds, means that the measure needs a two-thirds majority to pass. It’s not an impossibility — and the endorsement of The San Francisco Chronicle helps — but it’s not seen as likely.

The Berkeley measure is tamer: one cent per ounce (which is still almost 10 percent, about what it is in Mexico), with the taxes going into the city’s general fund, and therefore requiring only a simple (50 percent) majority. This, plus the fact that Berkeley is, well, “The People’s Republic of Berkeley,” makes it so that almost everyone I spoke to gives the Berkeley tax a far better chance of passing. Overall, this is a good thing; a real soda tax anywhere in the United States will demonstrate that the action is effective, and will encourage other municipalities and even states to consider it.

The soda industry does not really want to fight obesity. (It wants to fight soda taxes, and has spent more than $7 million doing that in San Francisco, a massive amount for a local measure.) Of course if it could replace all of its sugar with air, or make its profits by selling water, that would be fine. But if it were really interested in changing the status quo, it could stop marketing soda to children who are too young to figure out that it’s essentially poison (“a substance that is capable of causing the illness or death of a living organism when introduced or absorbed”) and could stop battling against taxes and public health campaigns designed to decrease its consumption. The industry will do neither of those things unless we compel it to. With time and patience, we will.