Now combine the subjectivity of the legal standard with the "stop/search" aspect (i.e., random checkpoints, with no basis for a police officer to suspect that a violation has occurred) through which it is often enforced. And then tell me how this isn't a textbook example of a police state in action.
I will admit that I am troubled by random checkpoints, not so much because of the fourth amendment violation—I’m not so sure that the temporary seizure rises to the level of a constitutional violation (but maybe it does)—but more from a fifth amendment self-incrimination standpoint. I really don’t buy into the “implied consent” argument, but on the other hand, I really don’t see any other workable way around the problem.
For instance, I think that were police to be barred from using DWI checkpoints, I think that police would be much more inclined to stop drivers for trivial violations—especially on Friday or Saturday nights, say—which would increase costs for the rest of society. Clearly these would be “sham” stops, and I’m not sure that’s better policy. Do you?