The US Supreme Court has agreed to decide whether motorists suspected of drink-driving who refuse to take a breath test can be forced to have their blood drawn at a hospital. A ruling in a case in the state of Missouri, expected next year, could help define the powers of the police and the rights of American motorists stopped for driving while intoxicated. In most states, failing to submit to a blood-alcohol can result in the loss of driving privileges. But judges in some states have balked at going further and forcing suspects to have their blood drawn against their will. Several states' courts have deemed this an "unreasonable search" in violation of the US constitution. The US high court said on Tuesday it would hear an appeal from Missouri prosecutors who argue that police need to act fast and require suspected drunken drivers to undergo either a breath test or a blood test. The American Civil Liberties Union argues that a police officer must obtain a search warrant before forcing a blood test.