Bennie Dean Herring was "no stranger to law enforcement," according to Chief Justice of the United States John Roberts. That's Roberts' understated way of saying that when Herring walks into a room, reasonable people could be forgiven for hearing the theme music to "Cops" in their heads.

Herring visited the Coffee County, Ala., sheriff's department on July 7, 2004, to get something from his truck, which had been impounded. Mark Anderson, an investigator with the department, asked the county clerk if Herring had any outstanding warrants.

Some might say that when a law enforcement officer's first reaction upon laying eyes on you is to check for outstanding warrants, you've made some poor life choices.

Anyway, the clerk said no. Then Anderson asked if there were any warrants from the next county over. Voila, the clerk found one for Herring's failure to make a court appearance. Anderson and a deputy proceeded to arrest Herring and search him and his vehicle. They found a gun (which was illegal thanks to a previous felony conviction) in his truck and methamphetamine in his pocket.

Then the clerk said, in effect, whoops! That's an old warrant and it shouldn't have been in the computer any longer.

Herring and his lawyers argued that his arrest and subsequent conviction were unconstitutional since law enforcement didn't have probable cause to conduct a search. The Supreme Court, in a 5-4 decision, disagreed this week. Legal observers are debating whether Herring v. United States is a landmark curtailment of the exclusionary rule or a small technical correction. Alas, out of concern for the status of my eternal soul, I refrained from becoming a lawyer, so I'll let others hash out that question.

Meanwhile, some of my libertarian friends are vexed by this. Glenn Reynolds (the 800-pound gorilla blogger known as Instapundit) writes in the New York Post that police shouldn't be exempt from following the law like everyone else. Reynolds understands the court's reasoning: "Why punish the police by letting a guilty man go free when they just made a simple mistake?" But, he reasons, ignorance is no excuse for John Q. Public, so why should it be one for Johnny Law? "Being a 'public servant,' apparently, means being free to make the kind of mistakes that the rest of us aren't allowed," writes Reynolds.

I've never understood this argument. Continued...