The Good Society
April 2023

Should we legalize marijuana? Actually, prohibition and legalization aren’t the only policy options. There are, broadly speaking, five:

  • Prohibition: production, sale, possession, and use of marijuana are illegal and subject to criminal penalty (imprisonment).
  • Decriminalization: possession and use of small amounts of marijuana are either permitted or subject to a civil penalty (a fine) rather than a criminal one.
  • Medical marijuana: sale and use of small amounts of marijuana is allowed for medical purposes when authorized by a licensed medical practitioner.
  • Legalization of small amounts: no penalty for production, sale, possession, or use of small quantities for recreational purposes.
  • Full legalization: production, sale, possession, and use are permitted with no limit on quantity (similar to how we treat alcohol).

Each of these approaches has multiple variants. And alongside whichever we choose, there are additional things that can be done, including taxation, education, and treatment.

Marijuana, opium, and heroin were widely used in the United States in the late 1800s and early 1900s. After World War I, the climate of public opinion toward drugs and alcohol changed considerably and many were outlawed. Even as late as 1930, however, only 16 states had laws banning marijuana use. In 1930 the Federal Bureau of Narcotics (FBN) was established as an agency to enforce drug laws. FBN officials began looking for ways to increase the agency’s visibility and importance, and so the agency launched a media campaign to convince the public that marijuana use was dangerous. The campaign was successful, and in 1937 Congress passed a law making marijuana illegal.

Our current policy is a complex hodgepodge. Under federal government law, production, sale, possession, and use of marijuana are illegal and subject to criminal penalty. But as figure 1 shows, nearly all of the states now take a different approach. In some states, decriminalization is the law: possession and use of small amounts of marijuana is either legal or subject to civil penalty (fine) rather than criminal penalty. In some others, decriminalization is the de facto policy approach, in that the penalty imposed for possession of small amounts tends to be lenient. In some states, production, sale, possession, and use of small amounts for authorized medical purposes is legal. Some states have both decriminalization and legal medical marijuana. Finally, in about one-third of the states, production, sale, possession, and use of small amounts for recreational purposes is legal.

Figure 1. State marijuana laws
White: prohibition. Light gray: decriminalization and/or legal medical marijuana. Dark gray: legal production, sale, possession, and use of small amounts for recreational purposes. Data source: “Legality of Cannabis by U.S. Jurisdiction,” Wikipedia.

Figure 2 shows the evolution of this legal landscape over time.

Figure 2. State marijuana laws
Number of states. Some states are in more than one group (e.g., both “legalized: medical” and “legalized: recreational”). Data source: “Timeline of Cannibis Laws in the United States,” Wikipedia.

What’s the best policy? Debate focuses on seven issues: freedom, pleasure, medical benefit, wasted lives, crime, the cost to taxpayers, and confidence in government. Let’s consider these in turn.

Skip to:


On one view, the government has no business preventing people from harming themselves. It should only prevent us from harming others. Production, sale, and use of narcotics therefore should be allowed. Laws should punish actions that endanger or harm others, such as driving while intoxicated.

Others feel this conception of freedom is too limited. Some restrictions on our behavior, such as seat belt requirements and mandated vaccinations, limit our freedom in one way but expand it overall. By keeping us safe and healthy, they allow us to enjoy other freedoms.1


Like alcohol and other intoxicating substances, marijuana is pleasurable to some people. It may also enhance enjoyment of social interaction, food, music, humor, and sex. When marijuana is prohibited, some people are denied access to this pleasure. And for those who use marijuana despite the prohibition, fear of the consequences of getting caught will tend to reduce the pleasure.

The pleasure criterion favors legalization or decriminalization over prohibition, but it doesn’t necessarily favor legalization over decriminalization, since for most users all that’s needed is the ability to purchase, possess, and use small quantities.


Most Americans support medical marijuana. A 2014 CNN poll found 88% agreeing that “adults should be allowed to legally use marijuana for medical purposes if their doctor prescribes it.”2

Does marijuana have medical value? According to Tracy Caulkins and colleagues, “Proponents point to marijuana as having therapeutic value in treating a range of symptoms; among the most common are appetite loss, nausea, chronic pain, anxiety, sleeping disorders, muscle spasms, and intraocular pressure. A (relatively small) number of controlled studies show marijuana or cannabis-based medicines relieve some of these symptoms. Opponents counter that other approved therapies for these conditions exist and are as effective, or more effective, than marijuana.”3


Drug use and abuse can wreck careers, relationships, families. And it can kill.

Currently, about 40% of Americans try marijuana at some point in their life. About 10% are semi-regular or regular users. About 2% are marijuana dependents or abusers.4 How much would use and abuse of marijuana and other drugs increase if we change our policy?

Drug prohibition reduces drug use by increasing the monetary price of the drug and by increasing the fear of getting sent to prison. But there are likely to be diminishing returns to prohibition; beyond a certain point, increasing the intensity of enforcement and/or punishment will reduce use only a little.

Our experience and that of other countries suggests that, compared to prohibition, decriminalization doesn’t tend to increase marijuana use by very much, if at all.5 The Netherlands legalized sale and consumption in “coffee shops” in 1976. Access remained limited and production remained illegal, so prices did not drop. Use roughly doubled. Portugal decriminalized possession of marijuana in 2001, though production and sale remained illegal; marijuana use and abuse have not increased. In the United States, the number of people incarcerated for drug-law violations increased tenfold between 1980 and 2010, but drug prices actually declined and drug use decreased little if at all. The US has been much more aggressive than other rich countries in arresting and jailing users, but patterns of marijuana use over the past generation — rise in the 1970s, decline in the 1980s, rise in the 1990s, decline in the 2000s — seem to have been similar in most countries. Some states in Australia have decriminalized, whereas other haven’t; patterns of marijuana use are similar across these states. In the US, some states have decriminalized while others haven’t; patterns of marijuana use are similar across these states. Marijuana use hasn’t increased more in states that allow medical marijuana, though it does appear to have risen more where medical marijuana can be purchased in legal dispensaries.

What about the effects of legalization? Until very recently, no modern country has done this, so we have very little evidence to draw upon.6 As figures 3 and 4 show, casual use and problem use are far greater for our two legal drugs — alcohol and tobacco — than for marijuana or any other type of illegal drug. One estimate suggests that legalization would likely result in a price drop of 70-90%, and that this might increase use approximately threefold.7 Another projects a doubling or tripling to be the most reasonable guess.8 How much would it increase heavy use? We don’t know.

Figure 3. Substance use in the past month
Share of Americans aged 12 and older. The “other illegal drugs” are psychotherapeutics (nonprescription), cocaine, hallucinogens, inhalants, and heroin. Data source: Substance Abuse and Mental Health Services Administration, Results from the 2013 National Survey on Drug Use and Health: Summary of National Findings, NSDUH Series H-48, 2014, tables 7.3b, 7.29b.

Figure 4. Substance dependence or abuse in the past year
Share of Americans aged 12 and older. The “other illegal drugs” are psychotherapeutics (nonprescription), cocaine, hallucinogens, inhalants, and heroin. Data source: Substance Abuse and Mental Health Services Administration, Results from the 2013 National Survey on Drug Use and Health: Summary of National Findings, NSDUH Series H-48, 2014, table 7.40b.

Is marijuana a “gateway” drug? Would its increased use also increase use of more dangerous drugs? There is a plausible causal link — enhanced desire to try other mind-altering substances and belief that they don’t do much harm, and enhanced connections with others who use and/or supply illegal drugs (the Netherlands’ coffee shop approach aims to reduce these supply connections). And people who smoke marijuana are much more likely to use and abuse harder drugs. But this correlation might not be causal: people may use both marijuana and other drugs because of some other factor, and perhaps they try marijuana first because it’s cheaper and more readily available. Only about 10% of people who use marijuana go on to have a substance abuse problem.9 So is marijuana a gateway drug? Very likely yes, but the effect seems to be pretty small.

Would increased marijuana use lead to more injuries and deaths due to intoxicated driving? We don’t know. Drivers who test positive for marijuana are much less likely to have been involved in a car crash than those who test positive for alcohol, but this may simply be a consequence of the fact that the roadside marijuana test catches not only recent use but use over the prior several days or even weeks, so many of those testing positive may not actually have been stoned at the time they were tested.10 While minor car accidents have increased more in states that have legalized marijuana, fatalities from car accidents haven’t. That is consistent with a finding that state adoption of medical marijuana didn’t result in an increase in car accident deaths.11

Angela Hawken argues that there is an effective way to address the worry about a rise in intoxicated driving12:

“Although DUI/DWI programs have a poor record of managing repeat violators, new programs show great promise, notably South Dakota’s 24/7 Sobriety program for drunk drivers. As the name implies, the program requires that chronic DWI offenders remain sober all the time, rather than allowing them to drink but forbidding them to drive drunk. Offenders must present themselves twice daily to the sheriff’s office and submit to a breath-alcohol test; anyone who tests positive is immediately jailed. For such a simple program, it has produced impressive results. Participants show up, sober, for more than 99 percent of their scheduled tests, and DUI recidivism has plunged…. It is easier to monitor compliance with abstinence from marijuana than from alcohol as marijuana has a much longer window of detection. Monitoring abstinence for repeat marijuana-DUI offenders would be logistically much simpler; weekly rather than twice-daily testing would suffice.”

A final consideration sometimes raised is that legalizing a drug allows it to be regulated to ensure quality and safety. No one dies anymore from poisoned alcohol. However, this isn’t a significant problem with marijuana, so the point isn’t especially relevant.

Currently, illegal drugs are estimated to kill about 25,000 Americans each year. Alcohol kills about 100,000.13 To put this in perspective, about 600,000 Americans are killed by heart disease each year, 580,000 by cancer, 120,000 by accidents. Around 35,000 die from suicide. About 15,000 are murdered, 11,000 with a gun. Decriminalization of marijuana probably wouldn’t increase deaths by very much. But would legalization? How many deaths would be too many?


Legalization of use and/or selling and/or production obviously would reduce crime in the sense that it would make currently-illegal activities legal. But the main interest here is what the impact would be on violent crime.

There could be a large effect on violent crime in Mexico and other marijuana-producing countries: killings by drug cartels might decline significantly if marijuana prices in the US drop and production here is legalized. What about violent crime here in America?

Revenues from sales of illegal drugs are about $60 billion a year.14 By reducing the price, legalization would reduce the profit from dealing. It thus would reduce the incentive for dealers to kill each other. But dealing-related violence in the United States comes mainly from harder drugs — cocaine and crack, meth, heroin — rather than marijuana, so changing marijuana policy might not reduce violent crime.15

If legalization increases drug use, that might cause more crime. Drugs impair judgment. Nearly half of all violent crime is committed by people under the influence of alcohol.16 And addicts commit crime to finance their habits, though this applies more to hard drugs than to marijuana.

What does the evidence say? Would marijuana legalization reduce violent crime? Do we need legalization in order to reduce violent crime?17 Conventional wisdom holds that prohibition of alcohol from 1919 to 1933 increased violent crime. That’s true in one respect: bootleggers began to kill one another in order to secure their turf. Yet violent crime and homicide from drunkenness decreased. Overall, the data suggest little or no change in violent crime during or after Prohibition. Most other industrialized countries have relatively tough antidrug laws like we do, yet drug-connected violence and homicide are far more common here in the United States. That’s not what we would expect if drug prohibition is a major cause of violent crime. In New York City from 1990 to 2010, violent crime decreased by 80%. This happened despite no change in drug policy or in drug use.


Prohibition has significant financial costs, which should be considered in weighing policy options.18

Each year 500,000 to 750,000 Americans are arrested for possession of small amounts of marijuana. This requires lots of police and administrators. About 40,000 are in prison or jail for marijuana-related crimes, with each inmate costing about $30,000 per year. All told, legalization might, according to one estimate, save about $8 billion a year in enforcement and imprisonment costs.19 Others suggest that figure is too high.20

A tax on legalized marijuana might raise about $6 billion a year.21

Suppose marijuana legalization could save about $15 billion a year. While that’s only 0.1% of our GDP, it could, presumably, do a lot of good if directed toward treatment and prevention.


Ineffective policies can undermine the public’s confidence in government.22 For this reason, if government can’t effectively prohibit drug use, some feel it’s better not to try.


Most Americans prefer decriminalization to prohibition. In 2014, 76% responded “no” to a Pew Research Center poll question asking “If marijuana use is not legalized, do you think people convicted of possessing small amounts of marijuana should serve time in jail?”23

What about legalization? As figure 5 shows, in the 1970s and 1980s only a fifth of Americans were in favor. Since 1990 that share has steadily increased. Today 68% say they are in favor. Note, though, that while the survey question is about legalization, some or many respondents may have in mind decriminalization rather than true legalization. A 2016 survey found that only 20% favor legal marijuana use with no restrictions on the amount and no medical authorization.24

Figure 5. Marijuana use should be legal
Estimated share of American adults who think use of marijuana should be legal. Gallup question: “Do you think the use of marijuana should be made legal, or not?” Response options: yes legal, no illegal, no opinion. The line shows the share responding yes legal, with no opinion responses excluded. Data source: Gallup, “Illegal Drugs,” GSS question: “Do you think the use of marijuana should be made legal or not?” Response options: legal, illegal. Data source: General Social Survey,, series grass.


Prohibition of marijuana reduces drug use and abuse, but it constricts freedom, it has significant financial costs, and it may weaken confidence in government. The evidence on decriminalization in other rich countries and in some US states suggests that it would increase freedom and lower enforcement and prison expenses without causing much of an increase in drug use and abuse. Full legalization, akin to our approach to alcohol, would be unprecedented in the modern world. It would enhance freedom, but it might significantly increase the share of Americans who are heavy users (currently 2-4%) and it probably would be of little help in reducing violent crime. We’ll have more evidence soon, as a third of the US states have opted for legalization, though only of small amounts.

  1. In his On Liberty, an inspiration for the libertarian viewpoint, John Stuart Mill cautions that “If anyone saw a person attempting to cross a bridge which had been ascertained to be unsafe, and there were no time to warn him of his danger, they might seize him and turn him back without any real infringement of his liberty; for liberty consists in doing what one desires, and he does not desire to fall into the river.” 
  2. CNN poll conducted by Opinion Research Center, January 3-5, 2014. 
  3. Jonathan P. Caulkins, Angela Hawken, Beau Kilmer, and Mark A.R. Kleiman, Marijuana Legalization, Oxford University Press, 2012, p. 95. 
  4. Mark A.R. Kleiman, Jonathan P. Caulkins, and Angela Hawken, Drugs and Drug Policy, Oxford University Press, 2011; Substance Abuse and Mental Health Services Administration, Results from the 2013 National Survey on Drug Use and Health: Summary of National Findings, NSDUH Series H-48, 2014; Caulkins et al, Marijuana Legalization; National Institute on Drug Abuse, “Drug Facts: Marijuana,” 2016. 
  5. Kleiman et al, Drugs and Drug Policy; Caulkins et al, Marijuana Legalization; Erich Goode, “Legalize It? A Bulletin from the War on Drugs,” Contexts, Summer 2004; Michael Specter, “Getting a Fix,” New Yorker, October 17, 2011; Rosalie L. Pacula
    David Powell, Paul Heaton, and Eric L. Sevigny, “Assessing the Effects of Medical Marijuana Laws on Marijuana Use: The Devil is in the Details,” Journal of Policy Analysis and Management, 2015.
  6. Caulkins and colleagues, in Marijuana Legalization, write “Ten years ago Rob MacCoun and Peter Reuter, two of the most respected scholars in drug policy, wrote a book called Drug War Heresies, the culmination of a decade-long systematic attempt to learn about legalization from comparisons with other times, places, and vices (such as prostitution and gambling). It still stands today as one of the five most important books ever written in the field…. Yet its ultimate stance is agnostic about the consequences of marijuana legalization; such comparisons simply do not provide definitive guidance. The RAND marijuana modeling project — in which two of us have been deeply involved — tried to generate estimates from quantitative modeling. It reached a similar conclusion. Legalized commercial production is so unlike what has been done in the Netherlands, Australia, Portugal, California, or anywhere else for which reliable data exist, that predictions cannot be made with any precision.” 
  7. Kleiman et al, Drugs and Drug Policy, p. 22. 
  8. Caulkins et al, Marijuana Legalization, p. 179. 
  9. Kleiman et al, Drugs and Drug Policy, p. 6. 
  10. Richard P. Compton and Amy Berning, “Drug and Alcohol Crash Risk,” Research Note, National Highway Traffic Safety Administration, 2015. 
  11. Christopher Ingraham, “What Marijuana Legalization Did to Car Accident Rates,” Washington Post: Wonkblog, 2017; Julian Santaella-Tenorio et al, “US Traffic Fatalities, 1985–2014, and Their Relationship to Medical Marijuana Laws,” American Journal of Public Health, 2017. 
  12. Caulkins et al, Marijuana Legalization, p. 326. 
  13. Kleiman et al, Drugs and Drug Policy, p. 19. 
  14. Kleiman et al, Drugs and Drug Policy, p. 58. 
  15. Caulkins et al, Marijuana Legalization, pp. 130-31. 
  16. Kleiman et al, Drugs and Drug Policy, p. 19. 
  17. Kleiman et al, Drugs and Drug Policy, p. 23; Caulkins et al, Marijuana Legalization, ch. 14; Franklin E. Zimring, “How New York Beat Crime,” Scientific American, August 2012. 
  18. John J. Donahue III, Benjamin Ewing, and David Peloquin, “Rethinking America’s Illegal Drug Policy,” Working Paper 16776, National Bureau of Economic Research, 2011. 
  19. Caulkins et al, Marijuana Legalization, ch. 4; Jeffrey A. Miron, “The Budgetary Implications of Marijuana Prohibition,” in Pot Politics: Marijuana and the Costs of Prohibition, edited by M. Earleywine, Oxford University Press, 2010. 
  20. Caulkins et al, Marijuana Legalization. 
  21. Miron, “The Budgetary Implications of Marijuana Prohibition.” 
  22. Some conservatives and libertarians might be tempted to think that’s a good thing. But even they want people to have confidence that government can do some things well, such as protecting property rights or fighting wars. 
  23. Pew Research Center, “America’s New Drug Policy Landscape,” 2014. 
  24. Associated Press and NORC Center for Public Affairs Research, “American Attitudes toward Substance Use,” 2016.