PS. and on the subject of drunk driving, you are looking at it in black and white terms. It should be about driving impaired, not driving drunk. For most people it requires about 2 or 3 beers to be drunker than the legal limit, but most people who drink have built up an alcohol tolerance to the point where they are not effected by that amount. I know a guy that polishes off a 12 pack every Friday and drives home and he's never been in a car accident or even gotten a traffic fine, because he's used to drinking that much and it doesn't impair his ability to drive. So why should he get a ticket simply for consuming a product which is his legal right to do so?
what if you crash your car when you have drank less than the legal amount? who is to say what level that alcohol contributed to it? studies have shown that talking on a cell phone while driving impairs you as much as being drunk, but many states still have it legal to do that. How about driving while you are tired? that's just as bad, but how are you going to enforce that? and what if you just straight up are not paying attention while you are driving, which is perfectly legal and no less dangerous.
Police can't stop people unless they have reasonable suspicion that they have committed a crime. If someone is driving perfectly fine, then there is no reason to pull them over and check if they have been drinking. That is why required breathalyzers in cars should not be permitted, they are presumed guilt. that's also why we have a law that says the police can't install a camera in your house to watch your every move. would it catch some guilty people? of course, but it would violate 99% of innocent people in the process. If you are innocent, then you should not be treated like a criminal.