The government has all sorts of pay guidelines on what people can make, which makes it near impossible for them to retain talent. Most of the NSA guys I know put in 18 or so months, then go to Booz Allen and get contracted right back to the department they left at 4x the pay (one guy even got his same desk back).

Every time someone points out the "why'd they give a clearance to X person" argument, I point out that there are close to a million people with security clearances. No screening system is perfect, but for something being ran by the government it is pretty damn good.