Ben Franklin's precept that nothing is certain except death and taxes may be reworked by Mayor Luke Ravenstahl. He is thinking of following Philadelphia Mayor Michael Nutter's attempt to impose a 2 cents-per-ounce tax on sugary drinks, prime suspects in the nation's obesity crisis.

In other words, nothing is certain except death by obesity and taxes -- so why not impose the latter to help combat the former? While the mayor has not yet framed the question this way, he does recognize the health benefits.

Soft-drink manufacturers have cut back on selling full-calorie drinks to the nation's schools and on Tuesday PepsiCo said it would remove sugary drinks from schools worldwide. A city tax would be a logical step in the larger battle against obesity, even if that is a secondary concern.

The primary concern is that the financially ailing city needs more revenue, namely an extra $15 million a year for its pension system. Nobody likes taxes, but Mr. Ravenstahl's proposal for a tuition tax on students was bitterly fought by students and their colleges. Is this easier to swallow? It ought to be. In fact, it is reasonable to assume that if soft drink makers on their own raised prices by 2 cents an ounce, this would not be an issue.

Mayor Nutter's plan, which is being debated by his city council, would bring an estimated $77.2 million a year to Philadelphia. In Pittsburgh, the estimate is $25 million, which is still a helpful sum. Unlike Philadelphia, which has the power to move ahead if its council agrees, Pittsburgh needs legislative approval in Harrisburg to impose such a tax. The mayor will be speaking to lawmakers next week about this and other proposals.

On a sugary drinks tax, legislators for once should be sympathetic to the city, especially if Philadelphia goes ahead with it. In a sense, this would be an update of the "sin tax" concept. While it's not your father's sin tax, it's something that addresses the modern, killer malady of obesity. It's a slight imposition on people with a possible big payoff for the city.

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