Sheriff Dupnik

K-Lo, you're right: law enforcement people are not supposed to do politics. There is some unavoidable policy-making that has to be done by sheriffs, police chiefs, district attorneys, etc. They have to decide, for example, how to allocate their finite resources, which means some kinds of crime are made high enforcement priorities, while others mightn't be prosecuted at all. That's a political choice, but it is very different from getting into the middle of -- or, in Sheriff Dupnik's case, stoking -- a political debate over an offense that is the subject of an ongoing investigation.

The investigator's job is to be as rigorously unaffected as possible by the public debate. You're not expected to be completely objective -- who could be objective about murder? But you have to tune out the noise and do your job, which is to figure out what happened and how to prove it convincingly. We don't want law-enforcement people weighing in with their opinions about the case for the same reason that jurors get told to keep their thoughts to themselves until deliberations. Once you express an opinion, you have a natural interest in not being proved wrong.

That interest can affect and taint your fact-finding -- and even if it doesn't actually affect your fact-finding, there will be a public perception that it might have affected your fact-finding, which undermines the integrity of the investigation and eventual trial. That's why the legal standard for recusal of a lawyer or judge from a case is "the appearance of impropriety." As a society, we accept the legitimacy of rulings by our legal system because we believe they are fact-based, not the result of bias. If a law-enforcement officer's biases appear to be affecting the process, the process is not legitimate -- regardless of whether it happens to produce accurate results.

Andrew C. McCarthy