[9] Support for Proposition 47 largely hinged on concerns about the overcrowding of California prisons, deemed an Eighth Amendment violation by the U.S. Supreme Court in 2011,[10] as well as arguments for the reallocation of funds to other crime prevention measures.

[13] Some local officials have also blamed the state's increase in homelessness on Proposition 47, which eliminated the legal compulsion of treatment for those struggling from addiction and mental illnesses.

"[21] The California Legislative Analyst's Office claims that Prop 36 would cost the state tens of millions of dollars in policing and incarceration,[22] funds that currently support mental health and drug treatment programs.

[23] Immigration advocates have expressed strong concerns about Proposition 36, arguing that it could lead to an increase in deportations of non-citizen Californians, including green card holders, DACA recipients, and refugees.

[24] Grisel Ruiz, a supervising attorney at the Immigrant Legal Resource Center,[25] warned that Prop 36 would significantly increase the number of illegal aliens facing deportation.

For example, if petty theft misdemeanors become reclassified as felonies, then more immigrants—including green card holders—will be barred from obtaining legal status and may lose any legal status they previously had, including their ability to obtain a green card and their ability to access valuable waivers to fight deportation cases, "which means deportation even if that would cause USC [U.S. Citizen] or LPR [Lawful Permanent Resident] dependents extraordinary hardship.

The California Budget and Policy Center warns that Proposition 36 may impose additional unfunded financial burdens on both state and local governments.

According to a report released by the office of Governor Newsom (who actively campaigned against the measure), Proposition 47 had generated an estimated $95 million in savings for the 2024-25 state budget.

The misdemeanor chargee imposes less of an impact on incarcerated people's future employment opportunities and access to housing, which creates additional cost savings.

[29] If Proposition 36 were to be enacted, the savings would diminish by tens of millions of dollars, according to the Legislative Analyst's Office (LAO),[30] or potentially vanish entirely, per the Center for Social Justice (CSJ) assessment.

Essentially, Proposition 36 would shift tens of millions of dollars annually away from behavioral health services and other initiatives back into the state prison system.