Why are some federal prosecutors and senators so eager to waste resources on lawbreakers who do us no harm?

Should the agency charged with stopping terrorists, human traffickers, and international street gangs spend time going after online poker sites? That's what the FBI has done. How many man hours did agents spend preparing the case? Surely federal law enforcement has better things to do.

Or maybe not.

After all, they spent roughly ten years and more than $55 million trying to convict Barry Bonds and other professional athletes in the BALCO case. They largely failed in their highest profile efforts. But what if they'd succeeded?

Would that have been worth it?

Should the federal government take U.S. Attorneys working on defense procurement fraud, illegal dumping of dangerous chemicals, civil rights violations, or schemes to bilk Medicare out of millions, and reassign some of them, so that their average day entails sitting at a desk, clicking through to various hard core porn Web sites, and deciding which of them most egregiously offends community standards?

Forty-two members of the Senate think so!

In their letter urging Attorney General Eric Holder to focus "vigorously" on "major commercial distributors of hardcore adult pornography," they didn't specify on which crimes he ought to lavish fewer resources. But that's how it works. It takes years to start an obscenity investigation, gather evidence, make arrests, and prosecute a major business enterprise. Every case undertaken has a huge opportunity cost.