Last week, we told you about Philadelphia Mayor Michael Nutter’s faulty memory and attempt to re-introduce an unpopular tax on soda that was soundly defeated by the City Council just last year. But Mayor Nutter’s memory isn’t the only thing that’s failing: A two-cents-per-ounce excise tax on soda to plug the city’s budget gap may sound attractive, but such taxes have never worked in any other city. And as we’ve told Philadelphians on television, any new tax receipts could disappear into government programs that have nothing to do with public health.

Tax proponents say it would have the dual effect of getting citizens to slim down by cutting back on soda, and of raising money to shore up the $629 million education budget gap. Both premises are false.

Researchers from Yale University, Bates College, and Emory University have found that taxes on sugar-sweetened beverages have no measurable effect on reducing citizens’ weight. Where such taxes do succeed is in putting the burden on the poorest populations – those least able to afford more expensive food.

Beyond that, politicians don’t have the best track record of putting their money where their mouths are. We talked to Philadelphia’s WTXF Fox 29 News to explain why tax dollars supposedly marked for education may not get to their intended destination:

City budgets are fungible and frankly, just because they’re saying that this tax going to go to education, it frees up money for other things like bloated public-sector pension funds and a whole slew of unnecessary city services.

Before Philadelphians are asked to make tough choices and trust the city with more of their tax dollars, Mayor Nutter should ask himself what hard choices he plans to make to plug his city’s spending black hole.