As far as it goes, the current investigation into fraud involving defense contracts is fine.

But it doesn't go far enough.The investigators should do much more than just take a close look at allegations of bribery and kickbacks. They also should examine the machinery for detecting and preventing such scandals. If they do, it's hard to see how investigators can avoid coming to the conclusion that some of this machinery is grossly inadequate.

We're referring to the provisions that rely on defense contractors to police themselves.

Two years ago, a blue-ribbon panel called the Packard Commission recommended more self-governance by contractors as an alternative to tougher regulation by the Pentagon.

In response to that recommendation, 46 corporations volunteered to participate in an ethics program that centers on policing themselves.

This week the Pentagon's deputy inspector general told the House Armed Services Committee that 39 of those firms are under investigation for procurement fraud.

Though investigations don't automatically equate with convictions, such substantial numbers make it hard to trust defense contractors to blow the whistle on themselves.

So much for the notion that an industry in which cost overruns are a way of life can be counted on to put its own house in order.

The lesson should be unmistakably clear: The Pentagon simply must stop relying on the industry to police itself and start monitoring defense contractors much more rigorously.