There are always concerns that city councilmembers can become too parochial, obsessing about how projects will affect their own districts rather than the city as a whole. In two cities, recent scandals have shown that this way of thinking can become an avenue to crime.

In both Chicago and Philadelphia, members of the city council are facing criminal charges that stem from development decisions. Councilmembers in those cities are given unusual amounts of authority when it comes to matters such as selling government-owned land. The practice is known as “aldermanic privilege” in Chicago and “councilmanic prerogative” in Philadelphia. Those terms are mouthfuls that barely hint at the kind of power bestowed on these officials. “With the strong district system that we have and councilmanic prerogative, it seems like it’s taken the mayor out of land use planning as a major player,” says Jon Geeting of Philadelphia 3.0, a local government reform group.

Lone councilmembers can decide if and when a project will move ahead. Not surprisingly, this creates real problems. In order to ensure get projects off the ground, developers know to approach councilmembers first, before there’s been a zoning change or request for sale or some other action that’s going to be made public. “A developer, by the unwritten rules of councilmanic prerogative, has to get the favor of a council person at a very early stage,” says Larry Eichel, who directs the Pew Charitable Trusts’ Philadelphia research initiative. “None of that is going to be transparent.”

This can have a number of ill effects. There’s the obvious danger of sweetheart deals, with politicians ensuring that their friends and campaign contributors get more than their share of the development action. But it can also serve to slow progress, with councilmembers refusing to greenlight projects in their districts. They may reject construction of a hospital, say, or a large mixed-use development the city may need after they’ve been hit by neighborhood opposition. Academic reports have found, and lawsuits have alleged, that the practice serves to perpetuate racial segregation.

Councilmembers insist they know their districts best. And there’s certainly an efficiency argument to be made, that cities are better off letting aldermen handle local problems without involving the entire council in relatively minor matters. But in practice, it’s clear that some leaders have exploited their positions, lining their own pockets by granting or withholding favor. In a system of checks and balances, granting councilmembers the authority to make executive decisions can be a recipe for corruption.

The high-profile criminal cases in Chicago and Philadelphia happen to have occurred in time for this year’s local elections. Privilege and prerogative have gone from terms commonly heard only around City Hall to subjects being talked about by candidates promising to pursue reforms. Chicago Mayor-elect Lori Lightfoot called reforms a “top priority” after winning election last month.

On the other hand, in both cities, these powers are for the most part not written down. Instead, a combination of tradition and professional courtesy has not only kept them intact but expanded their reach. The actions allegedly taken by longtime Chicago Alderman Ed Burke, which led to federal charges, were rooted in how he used his influence, not abuse of a formal power. And courtesies aren’t always observed. A major development known as Lincoln Yards has been opposed by the local alderman, but those who represent three neighboring wards want it to happen, so it recently received a positive council vote.

In Philadelphia, the entire city council votes on projects that members who represent districts are pushing. But those votes are merely a formality. During a six-year period, Pew found, the council voted on 730 bills that were based on councilmanic prerogative. Each and every one of them passed -- all but four on unanimous votes. “The system lines up the incentives to act in a certain way,” Geeting says. “It’s hard, because it isn’t written down anywhere.”