How carefully should government employees be screened?

This morning brings news that an FBI employee has been arrested for spying. Beyond that is the juicy DRUDGE headline that as an Active Duty Marine he spied while on the Vice President's staff for both Gore and Cheney. The retired Marine is a naturalized U.S. Citizen from the Philippines. He has soiled the reputation of the hundreds of thousands of Philippino-Americans who have served our country honorably over the past century. In my time in the Navy I worked with and for hundreds of Philippino-Americans and never had reason to suspect a single one of anything except being hard workers and good shipmates. He should face charges of espionage and treason. I would not rule out the death penalty. Who thinks he should be treated like another recent Top Secret security clearance holder caught stealing classified material?

However, this case will also raise the question about how we screen people for security clearances. When someone is being considered for a higher security clearance a basic Special Background Investigation (SBI) is conducted. We learned after the Johnny Walker spy case the importance of conducting periodic reviews. Problem is the items reviewed during an SBI (police record, credit report, etc) are not likely to identify the spy who is doing it for ideological reasons. Unless we want to be a complete police state, characters like this may only be caught when they trip up. The most reliable method of catching espionage is vigilance of co-workers. If you work in an area requiring a security clearance you have the responsibility to to be aware of your co-workers and notice when something just doesn't seem right.