Three dozen Pennsylvania state representatives and five state senators are pushing back against Philadelphia's soda tax, saying it's unconstitutional and "will result in lost sales tax revenue."

Legislators filed a 64-page brief Monday, calling on the Commonwealth Court to overturn the 1.5-cents-per-ounce surcharge on soda and other sweetened beverages that went into effect on Jan. 1, the Philadelphia Inquirer reported. 

According to the brief, the sweetened beverage tax violates the Sterling Act, which prohibits Philly from taxing items already taxed by the state, as well as the Uniformity Clause of the Pennsylvania Constitution by applying the tax "based on quantity or volume, not value, a set percent, or capped amount."

The city counters the brief parrots legal arguments previously made by the American Beverage Association — arguments that proved unsuccessful

The bipartisan coalition of legislators across 28 counties, including Philadelphia, argue violations of the Sterling Act could negatively impact the state's budget, as well.

The city responded that such an assertion is unfounded.

"Our economist demonstrated that the PhillyBevTax would have little impact on state sales tax revenue and under certain circumstances could actually increase state sales tax revenue," said Lauren Hitt, the city's communications director.