high fructose corn syrup...
The reason the US uses high fructose corn syrup is b/c it is cheaper, in the US, than sugar.
The reason it is cheaper than sugar is our large tax subsidies for corn.
The reason we need to subsidize corn is because sugar is because, otherwise, it is non-competitive with sugar imported from central America.
It is non-competitive with central American sugar because labor in central America is dirt cheap and they aren't inconvenienced by our environmental regulations (drinking water tastes better well-fertilized, after all.)
The normal solution to this would be to apply tariffs to central American sugar, but we can't do that b/c it would violate the North American Free Trade Agreement.
I would assert that perhaps, instead of taxing soda extra, we could just, and I know this sounds crazy, but: We could just *not* subsidize it. But that would require a large chain of policy changes that are just infeasible: Anyone who doesn't like NAFTA is a crazy hippie socialist, and anyone who wants to lift corn subsidies hates the American people. (Though I find it hilarious that I've found a way to blame a portion of the US obesity epidemic on NAFTA...)
Enjoy that soda, Pirate Dave. We're all paying good money to ensure that it's as cheap as it is.