The enforcement of U.S. drug and alcohol laws has been a major priority for police and prosecutors since the 1980s. Law enforcement has devoted considerable resources to the prevention of drug

In 2000 the U.S. Law Enforcement Agency spent the largest percentage of its budget on cocaine-related enforcement. Heroin accounted for the second largest portion, followed by marijuana and methamphetamine.

Modern methods for enforcing drug laws and prosecuting offenders have changed in several ways:

• State legislatures have increased the penalties for drug trafficking and for operating a motor vehicle under the influence of alcohol or drugs.
• The U.S. Congress has made drug trafficking penalties more severe.
• Congress passed a law in...