I just came across an interesting study by the Congressional Budget Office. According to the CBO, it looks like most government employees are indeed paid too much. Oddly enough, the amount of being overpaid seems to be inversely related to education - the less education government employees have, the more they're overpaid.
Government employees with no more than a high-school education make about 21 percent more in wages alone than their private-sector counterparts and a full 72 percent more in benefits. On the high end, however, people with professional degrees and PhDs actually make less working for the government than they would in the private sector: 23 percent less in wages alone and roughly the same level of benefits.
Perhaps this explains, at least in part, how recent research (PDF) has shown that the government actually has no problem at all in finding qualified information security workers.