The Bay Area initiatives are expensive prizes. Unlike Philadelphia, where much of the battle was fought through lobbying, both California tax proposals must win passage by a majority of voters. That means both sides have invested in big public outreach campaigns.

Citizens have been inundated with pro- and anti-soda tax TV and radio commercials, and mailboxes are filled with direct mail from both sides. Canvassers are making phone calls and going door to door in the final days of the campaign. Dan Newman, a political consultant with SCN Strategies, who is working on the pro-tax campaign, said the volume of messages about the measures dwarfs the 2014 effort.

“It was intense and expensive, and folks were amazed in talking about it,” he said of 2014. “And it was nothing like this.”

The tax battle has also prompted accusations of skulduggery. The soda industry enlisted the help of several local grocers to pose for mailers and state their opposition to the tax. Several of them, later approached by pro-tax advocates and reporters, said they had been misled about the nature of the tax proposal. Others have become the subjects of negative Yelp reviews and threatened with boycotts, what an anti-tax campaigner described as “intimidation.”

The measures are similar in both cities: They would impose a tax of one cent per ounce of any drink with added sugar, including sugary soft drinks, iced teas and smoothies. The taxes would be imposed on beverage distributors, not at the checkout registers. The emerging evidence from existing soda taxes suggests those higher prices will be passed through to retailers and then to shoppers. If they are, they could result in a price increase of 67 cents on a two-liter bottle, or $1.44 for a 12-pack.

Those higher prices are intended to discourage shoppers from consuming so many sugary drinks, which have been linked to obesity, diabetes and tooth decay. The pro-tax side has been emphasizing the negative health effects of soft-drink consumption, and arguing the tax will make the city’s children healthier.