In a private meeting with four members of the School Reform Commission last winter, tensions between Superintendent Arlene Ackerman and Commissioner Heidi Ramirez bubbled over.

The commissioners were locked in a debate, and two of the four were disagreeing with Ackerman when she changed the topic to tell them that her African American female staffers had complained that a commissioner was "condescending" and "racist" toward them, according to sources with knowledge of the incident. After some discussion, Ackerman focused the allegation on Ramirez, who challenged it. Some saw the exchange as a move by Ackerman to disarm her chief critic, the sources said.

Ackerman, who is African American, acknowledged making the complaint about Ramirez, who is Hispanic. But Ackerman denied using the word racist and said she had been talking about the need for "cultural sensitivity" and thought it was important to report the complaint to the commission.

And while both women downplayed the role of race in their conflict, the incident revealed how contentious the relationship had become between two accomplished educators who had worked together only eight months. The dispute culminated last week in Ramirez's stunning resignation.

In separate interviews, both women said their disagreements were largely professional. Their battle, they said, was more about how much say the commission should have in setting the priorities of a district that spends $3.2 billion annually and serves 167,000 students. Their conflict was inflamed by Ramirez's background: She is the only academic on the five-member SRC.

Whether their rocky relationship led to Ramirez's resignation is in dispute. Also unclear is just what role ongoing state and city budget negotiations may have played, along with a desire by Republicans to get a seat on the all-Democratic commission.

Were politicians working behind the scenes to get Ramirez to exit - which would ease tensions on the commission and avert the possibility that Ackerman could leave in frustration only a little more than a year into her tenure? Or did they just begin to discuss a replacement after Ramirez told Gov. Rendell she was thinking of stepping down, about a month ago?

Rendell last week said he was considering a replacement suggested by Senate Majority leader Dominic Pileggi (R., Delaware). There was even speculation in some circles that two of the five seats may be given over to Republicans in exchange for support on Philadelphia's budget bills, scheduled to move through the Senate this week.

Through a spokesman, Rendell flatly denied any deal Friday night. Pileggi had previously said the prospect of a Republican's joining the SRC had no tie to the budget impasse.

The governor also said he had no intention of withdrawing from the Senate the name of Democrat Joseph Dworetzky, a lawyer and former city solicitor - whom Rendell also put forward when he renominated Ramirez in March.

Ramirez's departure was chilling to some district staffers, who say Ackerman is too authoritative and bristles at the slightest challenge to her decisions.

"People are afraid," said a principal who asked not to be identified for fear of retribution.

"For us to lose an SRC member of the caliber of Heidi definitely does not smell right."

Ackerman denied that she had lobbied legislators for Ramirez's resignation. She said she's neither responsible for the departure nor concerned that it happened.

"I will not own that," Ackerman asserted during an hour-plus interview in her office Friday afternoon.

But she said she was frustrated with the number of questions from Ramirez and the amount of research time they required of her staff, so much so that she said she had once asked Ramirez: "Would you like to be superintendent?"

Ramirez, who holds a Stanford doctorate and runs Temple University's Urban Education Collaborative, a teacher training and research program, knows policy, Ackerman said, but so does she. Ackerman has a doctorate from Harvard.

"What I have had that she hasn't had in the past are three school districts that I've run," Ackerman said. "She stopped with the policy, and I have been able to blend the policy with the operations."

Ramirez, however, said that she needed the information to fulfill her oversight duty as a commissioner and that when she couldn't get it, she felt she no longer could be effective and stepped down. Commissioners must know the needs of the district, its schools, and students to set a vision for the system and all the costs associated with those needs, she said.

She maintained that she had not been forced or asked to resign, but had known she'd eventually face another Senate confirmation vote and had been unsure of her support.

"I'm leaving the SRC with a heavy heart, but on my own terms," Ramirez said in an interview last week. "I stood up for the things I believe in, and I hope the community will continue to appreciate that."

She spoke highly of Rendell, who nominated her, and said he had never asked her to change her vote or compromise her integrity. She declined to comment on Mayor Nutter, who initially recommended to Rendell that she be appointed.

But Nutter's education secretary, Lori Shorr, said the administration supported both women: "Heidi and I were in pretty much constant contact. We've been supportive of her all the way along. We're also supportive of Dr. Ackerman."

The two women simply disagreed on the role a commissioner should play, Shorr said.

The most outspoken member of the commission, Ramirez was often the only commissioner asking publicly for answers on subjects ranging from contracts to teacher retention.

But behind the scenes, Ackerman said, the other members were inquisitive. Ackerman shared a log of all questions members have asked privately of her staff since Jan. 1, and Ramirez asked 29 of the 170.

Ramirez's tone, however, was different, perhaps because of her background in educational research, the superintendent said.

"When she asked a question, it often felt like it was a dissertation," Ackerman said.

Two days before the board was set to vote on Imagine 2014 in April, Ackerman's ambitious strategic plan, Ramirez submitted five pages of single-spaced questions.

Her staff did the best it could, Ackerman said. But the district simply doesn't have a research office dedicated to commission questions, she said.

Ramirez said she had asked for the information months before and "had not been answered. Information that had been promised had still not been delivered."

In general, Shorr said, Ramirez was not ignored and "got many answers."

Others took Ramirez's side and said her questions had been good and should have been asked and answered.

"As CEO of the school district, there were many days I wished the board would disappear," said former interim district chief Phil Goldsmith, "but a board plays a legitimate role. The SRC has a specific responsibility to provide oversight and monitoring. . . . To retain the trust and credibility of the public, it is important for SRC members to be asking appropriate questions."

Former commission members Martin Bednarek and James Gallagher, who both served with Ramirez, spoke in support of her.

"My view is the loss of Heidi Ramirez is quite significant," Gallagher said. "The children of Philadelphia are losing a talented, highly energetic, and very intelligent advocate."

In her first year at the helm, Ackerman has attracted supporters as well.

In April, State Sen. Anthony Hardy Williams (D., Phila.) went to a commission meeting to urge the members to act on Imagine 2014.

Ramirez had expressed concerns about a lack of detail in the plan. The district would not tell her, and officials say they do not know the total cost of the five-year plan.

"This is a plan that has been created by a leader, and we frankly need to get out of the way, step back, and let her do her job," Williams said to the panel.

Ramirez voted to approve Imagine 2014, but "only reluctantly," she said.

Ramirez's resignation has triggered outrage.

A group of Hispanic leaders who support her planned to meet this weekend to discuss their next move, said Patricia De Carlo, executive director of the Norris Square Civic Association.

"It's just really distressing that folks are appointed with an independent voice and then they get a lot of pressure for questioning and they get frustrated and resign," she said.

Recently, Ackerman said, some of her supporters warned her that trouble was brewing.

Two weeks ago, she said, concerned community members called her to a "clandestine location" for two meetings. The community members, whom she declined to identify, warned her of an "all-out personal attack" before school began, and they feared she would leave.

Ackerman said she wasn't sure what it meant at the time, but now suspects they were talking about the Ramirez resignation.

Ackerman said she would not follow in Ramirez's footsteps.

"There are people who want me to leave," she said. "I am not going anywhere."

Contact staff writer Kristen Graham at 215-854-5146 or kgraham@phillynews.com.