Rebecca Rhynhart arrived at a Pennsylvania Society event Saturday morning ahead of her boss, Mayor Kenney, and lingered long after he moved on to the next event.

Rhynhart mingled at the Penn Club breakfast in her official capacity as Kenney's chief administration officer.

But she was also sizing up support for a potential Democratic primary election challenge to City Controller Alan Butkovitz.

This could get ugly. In a way, it already has.

Before Kenney created her post when he took office in January, Rhynhart served first as Mayor Michael Nutter's city treasurer and then as his budget director.

Nutter and Butkovitz clashed in August about an audit of proceeds from the Philadelphia Marathon.

Butkovitz said Nutter and his staff used more than $380,000 as a mayoral "slush fund."

Nutter called Butkovitz "a liar, a snake, and a hypocrite."

Nutter's former city representative, Desiree Peterkin Bell, went even further, suing Butkovitz, claiming he had defamed her.

Salty stuff.

Rhynhart didn't want to talk about her old boss or her potential opponent in the May 16 primary as she worked the room at Pennsylvania Society, a gathering of Pennsylvania politicians in New York each December.

Nutter and Kenney did not respond to questions about Rhynhart's potential candidacy.

The city controller is a financial watchdog for Philadelphia's governmental agencies. It would have been interesting to hear Nutter and Kenney talk about how the power of that post might be wielded by someone with close ties to the Mayor's Office.

Butkovitz, who apparently learned of Rhynhart's ambitions when I called him Saturday, suggested Nutter may have pushed her to run.

The former mayor, Butkovitz said, has been "off the wall" since the audit of the Mayor's Fund For Philadelphia, the city-run nonprofit used to hold the marathon money, went public in August.

"This sounds like a Nutter ploy," he said. "Nutter has been calling around, looking for an opponent ever since our initial Fund for Philadelphia audit."

Rhynhart, 42, who has a master's degree in public administration, worked in finance for seven years before joining Nutter's staff in 2008.

She later said it was "a little bit patronizing" for Butkovitz to claim she was Nutter's candidate. Judge her by her own credentials, she asked.

"I'm definitely giving it serious thought," Rhynhart said of the city controller race. "I think I'm very well qualified for it."

She'll have to make a decision soon. Becoming a candidate in the primary, just five months away, would require Rhynhart to resign from Kenney's staff.

"If I decide to do it, it would have to be a very quick time frame," she said.

Butkovitz, 64, is a ward leader and former state representative and is seeking a fourth four-year term. He skipped Pennsylvania Society this year.

This was the first time Rhynhart had traveled to New York for the event.

"I would say that I'm definitely developing contacts that could be useful going forward," Rhynhart told me before heading back into the crowd.

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