Rep. Chaka Fattah’s swift decline in the latest poll on the May 15 Democratic mayoral primary in Philadelphia may be directly attributable to the TV ads of one of his deep-pocketed opponents.

After leading in most polls for the better part of a year, Fattah found himself running second to businessman Tom Knox (D) in a Keystone Poll conducted March 28-April 3 by Franklin & Marshall College.

In the poll of 364 registered Democrats, Knox was ahead with 24 percent of the vote, Fattah was next with 17 percent, and Rep. Robert Brady (D) had 16 percent. Former City Councilman Michael Nutter (D) was at 12 percent, and state Rep. Dwight Evans (D) took 10 percent. The poll had a 5.1-point error margin.

Knox, who was barely known at the start of the campaign, is a wealthy self-funder who has bombarded the airwaves with TV ads produced by veteran Democratic strategist Joe Trippi. And they’ve probably made a difference: 53 percent of those surveyed said Knox’s ads were the most memorable of any of the candidates. Eighteen percent of the respondents said Brady’s ads were the most memorable.

In such a heavily Democratic city, the winner of next month’s primary is almost certain to succeed outgoing Mayor John Street (D) in January.

— Josh Kurtz