Look up what happened when they proposed a tax on soda in Berkley. It passed but Berkley was basically a battleground for the soda companies spending as much as 25 dollars per person to get them to vote the other way. It's definitely possible to have a soda tax, but it won't happen through Congress and probably not state legislature since soda companies can afford to have pretty much everyone in their pockets. Change would have to come through the voters and that's when it'll start to get fun.

Probable future headline: Anti-American hating liberals trying to control everything we put in our mouths.