I am curious, how do you think the police should be able to look for people drink driving?
Should they need to see you do something legal but seriously stupid like weaving between the lanes of the highway like a jackass before they can breathalyse you? Or should you actually need to break the law by running a red light? Or should they only be able to breath test people who crash?
Any of these would likely be "probable cause" under U.S. law to make a traffic stop. Under U.S. law an officer cannot detain you without either a warrant or probable cause. (At least, not in theory.)