Federal Employees are union members. This whole bill was a targeted pork project to pay back union members for the big win. Remember the fact that federal employees are not subject to the same rationalized health care that the rest of us will have, nor do they pay into social security.
Actually that's not entirely accurate. Some federal employees pay into social security, some do not. It depends on what agency they work for, when they came into the system, and under what terms. I'm not clear on all the details, but I know other FReepers have a much better understanding about this than I do. Maybe somebody else can shed more light on this. I also know I worked for a federal agency in the 80s and had social security withheld.