The Katz campaign said that the early attack ad was a "scare tactic" and a sign of weakness on Street's part, while the mayor's spokesman said that the Republican challenger slung mud first.
The Street ad opens with a picture of Katz next to the GOP's red, white and blue elephant logo.
"Republican Sam Katz has a very Republican plan," a narrator says. The ad goes on to say that the plan would "blow a hole in the city budget" and then recites accomplishments of the Street administration.
"Philly can't afford to clean up after this elephant," an announcer says, as a broom pushes away the picture of Katz and the logo. "Vote Democratic."
Street strategists have been clear that they would use Katz's party against him. Democrats have a 4-1 registration edge over the GOP in the city, and no Republican has been elected mayor in more than five decades. Street used similar appeals to party loyalty against Katz in 1999, but not until the closing days of the campaign when polls showed the election was too tight to call.
"John Street has to frighten people because he has no new ideas to grow the city," said Katz spokeswoman Maureen Garrity. "This is a mayor with no vision."
Katz has proposed cutting the wage tax by 22 percent and financing the immediate revenue loss with $750 million in bonds. Citing economists, he says such a cut would generate 63,000 new jobs.
"The last time we heard a Republican say he could cut taxes, grow the economy, and balance the budget was when George Bush ran for president in 2000," said Street spokesman Dan Fee.
"Wasn't true then, and isn't true now," Fee said.
Contact staff writer Thomas Fitzgerald at 215-854-2718 or tfitzgerald@phillynews.com.