America has the highest incarceration rate in the world. In 1971, different stops on drugs had been implemented for more than 50 years (for e.g. since 1914, 1937 etc.) with only a very small increase of inmates per 100 000 citizens. After 1980, the situation began to change. In 1994, it was reported that the "War on Drugs" resulted in the incarceration of one million Americans each year. Of the related drug arrests, about 225,000 are for possession of cannabis, the fourth most common cause of arrest in the United States.
In 2008, 1.5 million Americans were arrested for drug offenses. 500,000 were imprisoned.