Gangs

Organized Crime | Week 5, Lecture 9

Professor Julian E. Gerez

April 27, 2026

Roadmap: Gangs

  • Last time: trafficking
    • Any questions from last time?
  • Today:
    • Street and prison gangs
    • Further final project discussion time

Street gangs

What is a gang?

  • Our definition of organized crime (Varese, L2) centers on governance
    • Controlling markets, providing protection, enforcing rules
  • A gang is a compact subunit: consistent locality-based criminal activity
  • It does not always necessarily govern markets for others, just participates in them
  • Possible evolutionary path: Gang \(\rightarrow\) OC group \(\rightarrow\) mafia \(\rightarrow\) insurgency/paramilitary \(\rightarrow\) state ?

A color engraving of a chaotic street brawl between police in blue uniforms and gang members using knives, clubs, and chairs in early 1900s Paris.

Illustration of “Apaches” gang members fighting Paris police

Kamala Harris at a podium with the California DOJ seal, standing in front of large poster boards filled with mugshots and confiscated firearms on a table.

Kamala Harris announcing gang arrests in California, 2011

Why do people join gangs?

Push factors

  • Family instability and dysfunction
  • Poverty and lack of economic opportunity
  • Failure to form attachments to school
  • Exposure to violence in the neighborhood
  • Weak ties to conventional institutions

Pull factors

  • Physical safety and protection
  • Economic income (however modest)
  • Sense of belonging and identity
  • Respect, status, loyalty
  • Predictable social roles and rules

For discussion:

  • Which of these factors fit rational choice, social learning, or structural explanations for crime?
    • Which fit none of the above?
  • A pundit on TV says gangs form because of bad parenting. What’s missing?
  • Why do gangs cluster in particular neighborhoods rather than spreading evenly across a city?
  • If we eliminated poverty tomorrow, would gangs disappear?

Gangs require hospitable environments

  • Marginality: concentrated poverty + spatial isolation + institutional abandonment
  • Blocked opportunity: residents systematically locked out of mainstream labor markets
  • Illegible spaces (places outside the state’s administrative reach and oversight) provide
    • Cover from law enforcement
    • A captive market (residents with few alternatives)
    • A ready supply of recruits with weak ties to conventional institutions
  • These conditions make informal and illegal economies relatively more attractive

An aerial view of dozens of identical high-rise apartment blocks in a grid, surrounded by cleared land and older urban neighborhoods.

Former Pruitt-Igoe housing project in St. Louis.

Soldiers in camouflage stand near a car in the foreground, with the dense, hillside buildings of the favela rising into the clouds behind them.

Brazilian soldiers on patrol near the Rocinha favela entrance.

How are street gangs organized?

  • Remember the gang from L6? Franchise organization, hierarchical structure
    • Leader at top, officers below, foot soldiers at bottom
    • Revenues flowed up; orders flowed down
  • Most street gangs are smaller and flatter than that group
    • Shot caller or leader; core members; peripheral associates
    • Membership turnover is high: most members stay less than a year
  • The principal-agent and collective action problems (L5) still apply
    • No contracts, no courts, no formal HR
    • Violence, trust, and codes of conduct remain the primary solutions
  • The wage puzzle (L6) still applies: why accept low pay and high risk?
    • Tournament incentives: low expected wages, but nonzero chance of moving up
    • Non-economic benefits: belonging, protection, status

Prison gangs

The puzzle of prison gangs

Why does organized crime flourish in arguably the one place where the state is most present?

  • Weber (L3): the state holds a monopoly on the legitimate use of violence
    • Inside a prison, that monopoly should be absolute
    • Guards control movement, space, and resources
  • Olson (L3): a stationary bandit with a long time horizon provides order
    • The prison administration is the stationary bandit
    • It has every incentive to maintain order and suppress rival organizations
  • Yet: prison gangs are among the most powerful and durable criminal organizations in the world
    • They govern cellblocks, control contraband markets, and project power onto the streets
    • The state’s presence does not crowd them out (it may even enable them!)
  • For discussion:
    • The state is present, but does it care? Who bears the cost of prison violence?
    • Could the state’s own policies be making prison gangs stronger?

Why do prison gangs form and consolidate?

  • Many prisons rely on informal norms to govern inmate life
    • Reputation-based governance: inmates know each other; bad behavior has consequences
  • But norms are not enough and the state does not always step in: gangs fill the protection gap

Three shifts that enabled gang growth:

  1. Population explosion: ~200,000 people imprisoned in 1972 \(\rightarrow\) 1.5M+ by 2007
  2. Overcrowding: scarcer resources + more competition = greater need for protection
  3. Narcotics: surge in drug-related incarcerations created thriving illicit markets, made credible threats of violence profitable

A chart showing the US prison population which increases rapidly in the 1980s.

US State and Federal Prison Population, 1925–2023 (Bureau of Justice Statistics)
  • The US has 5% of the world population, but ~20% of world’s incarcerated people
  • These dynamics are not unique to the US, but the US is an extreme case

How are prison gangs organized?

  • Criminal groups solve organizational problems through violence, trust, and codes of conduct

Horizontal structure (e.g., Mexican Mafia)

  • One official rank; each member has a vote
  • Relies heavily on implicit rules and norms
  • Shot callers emerge informally at each facility
  • Small and selective: ~300+ full members

Vertical structure (e.g., Nuestra Familia)

  • Formal ranks: general, captains, soldiers, etc.
  • Written constitution with checks and balances
  • Described by a federal prosecutor as sophisticated as a Fortune 500 company

Other major prison gangs in California:

  • Black Guerilla Family: very politically organized; revolutionary ideology; military structure
  • Aryan Brotherhood: white supremacist; extremely violent; loose alliance with Mexican Mafia

Mexican Mafia symbol Nuestra Familia symbol Black Guerilla Family symbol Aryan Brotherhood symbol

News: Organized crime in Orange County

  • Take a few minutes to read this article and discuss with the people near you:
    • What made this organization so hard to take down?
    • What concepts from class help explain this?

43 Mexican Mafia Gangsters Arrested on Indictments Alleging Racketeering, Drug Trafficking, Kidnapping, Assault, and Murder

https://tinyurl.com/2026cls100

The prison-street nexus

  • Prison gangs do not stay behind bars, they project power onto the streets
  • The key mechanism: credible threats across the prison-street divide
    • Drug dealers on the street anticipate future incarceration
    • Associates already inside are vulnerable to gang violence
    • Paying “taxes” to the prison gang buys protection on both sides
  • E.g., the Mexican Mafia extracts 10–30% of revenues from Sureño street gangs in Los Angeles
    • Dealers who refuse to pay face assault when they eventually enter county jail
    • Dealers who comply receive protection inside and dispute resolution on the street
  • The gang’s leverage depends entirely on controlling what happens inside
    • Prison walls are the source of the gang’s power
  • For discussion:
    • If a gang governs a drug market and adjudicates disputes: is it still just a gang?
    • If prison is where these organizations form and consolidate, what does it mean to fight them by sending people to prison?

Final project discussion time (~25 minutes)

  • Think through what we’ve covered so far with relevance to your policy brief topic:
    • Origins, organization, protection, trafficking, etc.
    • What type of criminal organization is your case primarily about?
    • How does your case intersect with other types of criminal activity we have covered?
  • What is the relationship between your criminal group and the state?
  • What is the hardest part of your case to explain using course concepts so far?
  • Who is the audience you want to address in your brief?
    • A national government? An international organization? An NGO?
    • How do your policy recommendations change depending on the audience?

For Wednesday: Quiz 2

  • Today: street and prison gangs
  • Wednesday: Quiz 2 at the start of class
    • Taken on Canvas, so please bring your laptop
    • Same format as Quiz 1
    • Covers material through today’s lecture
  • We will then discuss other non-state armed actors and whether they are organized crime
  • Questions?