To help clarify a few things. In the case of Michigan vs. Stits, the Supreme Court did rule that Sobriety Checkpoints were in fact UnConstitutional. Although it was later overturned, Justice Renquist did declare that it was in fact UnConstitutional:US Supreme Court Ruled on this issue !!!!!
"In sum, the balance of the State's interest in preventing drunken driving, the extent to which this system can reasonably be said to advance that interest, and the degree of intrusion upon individual motorists who are briefly stopped, weighs in favor of the state program. We therefore hold that it is consistent with the Fourth Amendment".
Chief Justice Rehnquist began his majority opinion by admitting that DUI sobriety checkpoints do, in fact, constitute a "seizure" within the language of the Fourth Amendment. In other words, yes, it appears to be a blatant violation of the Constitution. However, he continued, "...it's only a little one, and something has to be done about the "carnage" on the highways caused by drunk drivers." The "minimal intrusion on individual liberties," Rehnquist wrote, must be "weighed" against the need for -- and effectiveness of -- DUI roadblocks. In other words, the ends justify the means.
There is no such thing as a "Little" violation of the 4th or any right for that matter. The Bill of Rights was written/composed for the common man to read and understand - to understand that those right are guaranteed. Can you imagine telling troops to fight wars based on, "You are fighting a war to protect a little bit of freedom or freedom deemed with exception?
The Supreme Court ruled unconstitutionaly and like anything else, you can ignore that ruling. If you think about it, when do they setup checkpoints for Cell Phone usage, or people eating and driving, from license & registration? Because they know it is intrusive. If the law is NOT effective then it is unconstitutional to enforce it. Checkpoints for DUI arrest are ineffective and the numbers prove it. The only arrests and citations they make are for registration & licensing etc.(Hoping you don't go with, "Well even getting one DUI arrest makes it worthwhile") We both know that the end doesn't justify the means. I am totally against the act of drinking & driving, but I also believe that we are a nation of laws, not men.