Where are the next battlegrounds for soda taxes?

As proponents of taxing sugar-laden drinks chalk up a second large win, coming initiatives in a handful of other U.S. cities could determine whether the practice becomes a trend or remains a rarity.

On Thursday, Philadelphia passed a tax on sugary soft drinks, following in the footsteps of Berkeley, California, the only other city in the country that taxes soft drinks. At least 40 other such efforts have failed, including in New York and San Francisco, and two previous attempt in Philly.

"Efforts to tax sugary drinks like tobacco -- as a health hazard -- have been beaten back by the deep pockets of the beverage industry over the last eight years," said David Goldberg of Healthy Food America, a group that advocates against the soda industry. "Philadelphia is almost certain to be a turning point. If it can win there, it can win anywhere."

Whether Goldberg's statement holds true will be tested in coming months with San Francisco, Oakland and Albany, California, and Boulder, Colorado, all weighing taxes on soft drinks before the end of the year.

So far, it's a battle largely won by the beverage industry, which has poured multiple millions of dollars into the effort, with nearly $5 million spent on advertising in Philadelphia alone.

"Similar tax proposals have been rejected 43 times across the country in the past eight years," the American Beverage Association noted in a statement. The trade group, whose members include PepsiCo (PEP) and Coca-Cola (KO), also says it'll fight the Philadelphia measure in court, calling it unlawful and discriminatory.

Already facing a public consuming fewer sugary drinks due in part to concern over health effects, including obesity and Type 2 diabetes, the sugar and soda industries are fighting back on multiple fronts, including sponsoring academic research.

A recent exclusive by the Associated Press found the candy industry, for instance, helped bankroll research by Louisiana State University that lead to headlines including this one from CBS: "Does candy keep kids from getting fat?"

That said, Philadelphia's Democratic Mayor Jim Kenney took a different approach than previous efforts raising health concerns. Rather than pitching the tax as a means of curbing consumption, the mayor instead portrayed the soft drink industry as a welcome means of funding programs like universal kindergarten, which are popular with Philadelphia's residents.

"This is the beginning of a process of changing the narrative of poverty in our city," Kenney told a news conference after Thursday's vote backing his plan to spend most of the estimated $90 million in revenue next year to pay for prekindergarten, community schools and recreation centers.

A penny-an-ounce tax on sugary drinks will be on the ballot in Oakland, California, in November, and if passed would bring in between $6 million and $10 million annually, according to estimates from the Oakland City Council. Similar initiatives are also taking place in San Francisco and Albany, California.

In Boulder, Colorado, signatures are being collected to get an initiative on the city's November ballot.

Most of rejections of proposals to tax soda came at the hands of state legislatures, where lobbyists might influence individual members. Coming efforts include ballot initiatives putting the question directly to voters, which could prove more difficult for industry groups to sway.

That proved to be the case in Berkeley, where voters in late 2014 approved by a 3-1 margin a penny-per-ounce tax after a battle in which the beverage industry spent more than $2.1 million fighting the initiative.