Drugs
‘War on Drugs’ in US since late 1960s heroin epidemic
powder cocaine epidemic (early 1980s)
crack cocaine epidemic (mid- to late 1980s)
methamphetamine epidemic (early 1990s - )
Drug arrests concentrated on black community:
吸毒被抓集中在黑社区
Rates of drug use very similar across races药物使用率在不同种族中非常相似
Most drug sales are amongst friends, likely to be of the same race大多数药物销售是朋友，可能是同一个种族
Street sales to people not known by the seller are a smaller part of the market but:街道销售卖给不认识的人是市场的一小部分，但是：
where most arrests occur
大多数逮捕发生
minority communities overrepresented
少数族裔所占比例过高
From 1986 to 2010, the penalty for possession of 50g of crack cocaine was 100 times that for the same amount of powder cocaine 从1986年到2010年，拥有50克crack可卡因的罚款是相同数量的可卡因粉末的100倍
Becker, Grossman and Murphy (2004)
If drug markets are perfectly competitive, firms earn zero profits:如果药物市场完全竞争，企业就可以获得零利润：
Resources devoted to drug production, smuggling and distribution, including cost of violent actions equals the revenues from drug sales专门用于药物生产，走私和分配（包括暴力行为费用）的资源等于药物销售收入
If demand is inelastic, a fall in consumption will increase revenues and hence resources devoted to supplying drugs如果需求无弹性，消费量的下降将增加收入，从而增加供应药物的资源
The more inelastic demand, the lower the marginal benefits of enforcement (everything else equal):需求更无弹性，执法的边际效益越低（一切平等）：
It reduces the quantity of drugs consumed (but this may or may not be a good thing)减少消耗的药物的数量（但这可能是或不是一件好事）
It raises the total cost (and revenue) of producers
提高生产者的总成本（和收入）
the increase in the unit cost of production leads to increase in price which more than offsets the reduction in output单位生产成本的增加导致价格上涨超过抵消产出下降的价格
the more inelastic demand, the higher the marginal costs of enforcement
Extra spending per unit of drug consumption can be more than offset by a fall in consumption if the elasticity of demand is high如果需求弹性较大，消费量下降可抵消每单位药物消费额外支出
It will not be if the elasticity of demand is sufficiently low如果需求的弹性足够低，则不会如此
Thus an inelastic demand (coupled with relatively small external social cost from drug consumption) would likely lead to spending on prohibition being sub-optimal.
Spending on drug enforcement is less likely to be optimal – only if the marginal external cost from consumption is very high 药物执法支出不太可能是最佳的 - 只有边际消费的外部成本非常高
Even then, the cost will be very high 即使这样，成本就会很高
Is demand inelastic?
All range from inelastic to somewhat elastic所有范围从无弹性到有弹性
Heroin: -0.25 to -1.80 (Jofre-Bonet & Petry (2008) -0.9 for addicts)
Cocaine: -0.72 to -2.51 (J-B & P (2008) -0.9 to -1.05 for addicts)
Marijuana: -0.36 to -1.51 (Kilmer et al (2010) point estimate -0.54)