In the 1700s, the state’s dominance over an individual in criminal proceedings was regarded as so overpowering that the Fifth Amendment guaranteed that citizens would not have to incriminate themselves through compelled testimony. In contrast, drug warriors argue that the power of an individual citizen is so overwhelming that government agents must be able to coerce self-incrimination.
One method is through urine tests after arrest for any crime. Results can be used to prosecute a person for “internal possession” of a drug, or even for earlier possession outside the body. At one time the U. S. Supreme Court forbade such prosecutions. Justice William O. Douglas explained, “Words taken from his lips, capsules taken from his stomach, blood taken from his veins are all inadmissible provided they are taken from him without his consent. They are inadmissible because of the command of the Fifth Amendment. That is an unequivocal, definite and workable rule of evidence for state and federal courts.”
In the name of drugs, however, police are now allowed to use physical bodies of suspects (that is, the status of what suspects are, rather than the conduct of what they do) to convict them of drug offenses.
(Taken from Drug Warriors & Their Prey – From Police Power to Police State – by Richard Lawrence Miller)