Roughly half of the money raised to oppose a ballot measure to legalize recreational marijuana in California is coming from police and prison guard groups, terrified that they might lose the revenue streams to which they have become so deeply addicted.

Drug war money has become a notable source of funding for law enforcement interests. Huge government grants and asset-seizure windfalls benefit police departments, while the constant supply of prisoners keeps the prison business booming.

Opposition to the marijuana legalization initiative, slated to go before voters in November, has been organized by John Lovell, a longtime Sacramento lobbyist for police chiefs and prison guard supervisors. Lovell’s Coalition for Responsible Drug Policies, a committee he created to defeat the pot initiative, raised $60,000 during the first three months of the year, according to a disclosure filed earlier this month.

The funds came from groups representing law enforcement, including the California Police Chiefs Association, the Riverside Sheriffs’ Association, the Los Angeles Police Protective League’s Issues PAC, and the California Correctional Supervisor’s Organization. Other donors include the California Teamsters union and the California Hospital Association, as well as Sam Action, an anti-marijuana advocacy group co-founded by former Rep. Patrick Kennedy, D-R.I., and former George W. Bush speechwriter David Frum.

Law enforcement officials in Minnesota, Washington, and other states that have debated relaxing the laws surrounding marijuana have said that they stand to lose money from reform. Police receive federal grants from the Justice Department to help fund drug enforcement efforts, including specific funding to focus on marijuana.

Asset forfeiture is another way law enforcement agencies have come to rely on marijuana as a funding source. Police departments, through a process known as asset forfeiture, seize cash and property associated with drug busts, including raids relating to marijuana. The proceeds from the seizures are often distributed to law enforcement agencies. From 2002 to 2012, California agencies reaped $181.4 million from marijuana-related asset seizures. As the Wall Street Journal reported in 2014, pot legalization in Washington state led asset forfeiture proceeds to go up in smoke.

Law enforcement lobbyists in Sacramento, including Lovell, have steered Justice Department grants into marijuana eradication. Last year, Lovell successfully worked to defeat measures to reform asset forfeiture in California.

Prison guard unions have also played a part in defending lucrative drug war policies. In California, the prison guard union helped finance the “three strikes” ballot measure in 1994 that deeply increased the state prison population. In 2008, the California prison union provided funds to help defeat Proposition 5, a measure to create prison diversion programs for nonviolent offenders with drug problems.

For their part, the groups say they fear the dangers of legalized pot for non-selfish reasons.

“The membership of the CCSO opposes the full-blown legalization of marijuana,” Paul Curry, a lobbyist for the California Correctional Supervisor’s Association, told The Intercept. Curry said prison guard supervisors do not want to see a society that encourages pot use and said many of his members are grandparents who are concerned about their children. “If marijuana is not a dangerous drug, the federal government would have made a change, but the fact remains that it’s a federal crime,” he added.

California is only the latest state in which law enforcement unions have led the opposition to ending marijuana prohibition across the country in recent years. During the 2014 election, Florida law enforcement officials successfully campaigned against a medical marijuana ballot measure by arguing that the initiative would promote a range of problems, from teenage use of the drug to respiratory disease.

In 2010, Lovell successfully organized a campaign to defeat a similar marijuana legalization ballot measure in California. That year, he raised funds from police unions, local prosecutors, and the California Beer and Beverage Distributors Association, in addition to several individual donors. (Presumably the beer distributors see legal pot as cutting into their business.) The initiative was defeated, even though Lovell was outspent by pro-legalization campaigners.

This year may be different. Supporters of legalization have already raised more than $2.25 million for the campaign — 40 times what opponents have — and recently secured a number of high-profile endorsements, including Rep. Ted Lieu, D-Calif. and the California Medical Association. Polls show Californians are even more in support of legalization this time around, with around 60 percent of likely voters claiming they will back the measure.