A few courts have intervened to protect the civil liberties of drivers:

Critics of the practice see a threat to privacy and civil liberties, with judges in Rhode Island, New Jersey and Wisconsin barring, limiting or questioning the practice in recent years. In Pennsylvania, the state police say they don't take blood if a driver refuses, but might if the driver is unconscious.

Doctors have balked at the practice as well:

For me to draw blood from a patient who is refusing to have his blood drawn, unless I have compelling medical reasons for that blood sample, I'm committing assault and battery, and I'm not going to do it," says Dr. Phil Brewer, president of the Connecticut College of Emergency Physicians and a fellow at the National Highway Traffic Safety Administration.

Would the Supreme Court uphold the practice today? The last time it considered the issue was in Schmerber v. California--in upholding the practice it stressed the way the blood was taken--in a hospital by a physician.

The majority warned that "serious questions ... would arise" if the blood were extracted "in other than a medical environment -- for example, if it were administered by police in the privacy of the stationhouse" because allowing that might "invite an unjustified element of personal risk of infection and pain." It added that "more substantial intrusions, or intrusions under other conditions" might not pass muster.

State and federal courts have countenanced a range of police conduct in obtaining blood, from putting a chokehold on the carotid artery of a suspected drunk in California to shooting one in the arm with a stun-gun in Delaware. And blood often is extracted in police lockups and jailhouses -- just the sort of environment the Supreme Court said might be constitutionally troublesome.