The Fourth Amendment of the U.S. Constitution guarantees the "right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures..." The expansion of police powers as part of the war on drugs has been one of the most significant challenges to the integrity of the Fourth Amendment.

In the context of the drug war, Fourth Amendment issues arise primarily from the search and/or seizure of people and their belongings in an effort to detect drugs and drug paraphernalia. Such searches and seizures take place on the streets, in cars, on public transportation, in homes, in the workplace and in schools - anywhere that people and drugs can be found.

Racial profiling, asset forfeiture and mandatory suspicionless drug testing - all tools of the modern war on drugs - represent some of the most serious abuses of Fourth Amendment principles and mark the steady erosion of constitutional protections.

Racial profiling is the practice of stopping, searching or targeting for investigation an individual on the basis of race, national origin or ethnicity. Rates of drug use or drug selling are no greater for members of minorities than for non-minorities, yet minorities are stopped, searched, arrested, prosecuted and incarcerated at far greater rates than whites. In addition, persons of color are typically sentenced to longer jail and prison terms than white counterparts convicted of identical offenses.

Civil Asset Forfeiture is the practice of law enforcement seizing and keeping money, property, and other assets which they suspect may have come from illegal profits - such as drug sales. Civil asset forfeiture often takes place without proof of the origins of the asset and without a conviction of anyone for wrongdoing. Law enforcement often retains the seized assets, or the proceeds from the sale of the assets, and uses the assets to fund further law enforcement efforts. As a result, a dangerous incentive is created for law enforcement to seize and keep assets at the expense of due process and individual liberties. Challenging civil asset forfeiture practices is a drug policy reform effort that has received considerable public support.