WASHINGTON - The Supreme Court is considering whether police must get a warrant before ordering a blood test on an unwilling drunken driving suspect.

Yesterday the justices heard arguments in a case involving a disputed blood test from Missouri. Police stopped a speeding, swerving car and the driver, who had two previous drunken-driving convictions, refused to submit to a breath test to measure the alcohol level in his body.

The justices appeared to struggle with whether the dissipation of alcohol in the blood over time is reason enough for police to call for a blood test without first getting a warrant.