But there's a more fundamental point. What precisely is being criminalized? Not bad driving. Not destruction of property. Not the taking of human life or reckless endangerment. The crime is having the wrong substance in your blood. Yet it is possible, in fact, to have this substance in your blood, even while driving, and not commit anything like what has been traditionally called a crime.

What have we done by permitting government to criminalize the content of our blood instead of actions themselves? We have given it power to make the application of the law arbitrary, capricious, and contingent on the judgment of cops and cop technicians. Indeed, without the government's "Breathalyzer," there is no way to tell for sure if we are breaking the law.

Sure, we can do informal calculations in our head, based on our weight and the amount of alcohol we have had over some period of time. But at best these will be estimates. We have to wait for the government to administer a test to tell us whether or not we are criminals. That's not the way law is supposed to work. Indeed, this is a form of tyranny.

Now, the immediate response goes this way: drunk driving has to be illegal because the probability of causing an accident rises dramatically when you drink. The answer is just as simple: government in a free society should not deal in probabilities. The law should deal in actions and actions alone, and only insofar as they damage person or property. Probabilities are something for insurance companies to assess on a competitive and voluntary basis.