Advocates of the prerogative say it lets local representatives protect neighborhood interests. Detractors say it opens the door for politicians to extract favors from potential buyers.
What no one disputes is that it gives Council members immense power over city-owned real estate.
"It makes the development process very arbitrary," said University of Pennsylvania economist Kevin Gillen, a local real-estate expert. "It's often done in a disingenuous way where the community doesn't really oppose the development, but they realize they can get something from the developer."
Already, Council members' fingerprints can be seen on potential school sales.
Councilwoman Jannie Blackwell, sources say, has threatened to oppose or delay the sale of University City High School in an effort to aid a favorite neighborhood group of hers.
Drexel University, which is interested in buying the school property, recently pulled $300,000 in annual funding from the Mantua Community Improvement Committee (MCIC), which depended on Drexel's money for most of its budget. Blackwell is said to be threatening to hold up the sale of the high school unless Drexel restores the money.
Blackwell said she is upset with Drexel's handling of MCIC aid, but has not made any specific threats regarding the sale - yet.
"I have a problem with Drexel if they fight a legitimate community organization. I have to support everybody [in the district]. How that translates, we'll see," she said. "No holds barred."
A Drexel spokeswoman confirmed that the university is interested in the high-school property and that it has cut off support to MCIC. But she declined to comment on Blackwell's involvement.
MCIC president Rick Young said Drexel had complained that his group, which employs disadvantaged neighborhood residents to clean up the area and put on charity events, was disorganized and didn't have a mechanism for tracking grants.
"It wasn't structured to what they think it should have been, but it never had to be. We were never under any contribution agreement," Young said. "We've never really had the funding to have a real internal processing of stuff. All our money went to making a difference in the streets."
An unrelated lawsuit filed against Blackwell by another local group describes MCIC as "subservient to her control and political objective" and called Young a "business partner and political supporter" of Blackwell's.
Mantua Community Planners, a decades-old group led by the Rev. Andrew Jenkins, filed the suit, which alleges that Blackwell has strong-armed them out of opportunities she is now funneling to MCIC "to silence anyone in her political district that was not directly controlled by her and/or through her protege, Young."
Blackwell did not return a call for comment on the suit.
She would hit the school-building jackpot under the Council plan: About half of the most desirable properties are in her district.
Pros & cons
Councilmanic prerogative, a term you won't find in the Home Rule Charter, is the unofficial agreement between Council members to defer to the district representative's preference when it comes to deals in that district.
Typical school district sales do not require Council approval. But under the Council plan, which passed out of committee last week, the city would either acquire the shuttered schools directly or buy them through the Philadelphia Authority for Industrial Development.
Those transactions would require Council approval, opening the door for members to hold things up.
Council president Darrell Clarke and Blackwell are the undisputed king and queen of prerogative.
Clarke currently has holds on 46 city-owned properties and Blackwell has 43, according to the Philadelphia Redevelopment Authority. Coming in a distant third is Councilman Mark Squilla, who has 11 open holds.
Many of Clarke's holds are in gentrifying areas around Temple University and Francisville. He said he holds up sales in those areas to slow the stampede of college students in the neighborhood and to ensure some money from the sales is used for affordable housing.
"There's too much student housing," Clarke said "It's just overwhelming the community."
Brian Abernathy, executive director of the Philadelphia Redevelopment Authority, said that Council members are usually trying to do what's best for their districts when they place holds.
But ending a hold often means meeting with various community groups, many of which demand funding for unrelated projects or neighborhood improvements.
"If someone isn't willing to meet with the neighbors and adjust their designs, there are going to be problems, and finding that line can be hard, but it is what it is," Abernathy said.
Because Council members can hold up a project for any reason, development in Philadelphia is perceived to be more risky than in other places, said Gillen, the Penn economist. Developments are often financed through loans, and that risk can increase costs.
"Why are there no major national developers in Philadelphia?" Gillen asked. "Most of our developers are all local."
On Twitter: @SeanWalshDN