I remember seeing a Dept of the Army Civilian during the run-up to my first deployment. He was helping us get our equipment and vehicles prepped for shipment. Anyway, his jacket of choice was one sporting the AFGE logo and motto "United we bargain, divided we beg". Really opened my eyes as to what the union mentality was and who he really thought he worked for.
For the DACs and most Federal civil service employees, there really isn't much to bargain about and whatever positive role the union fills is really more like an ombudsman. Federal pay and most benefits are set by Congress, no amount of whining from the union can change that, they have no right to strike, and the retirement system for anyone coming in after the mid-80s (Also set by Congress and non-bargainable) combines a very modest defined benefit plus a contributory 401k-type thing called Thrift Savings Plan. That slogan was pretty much completely empty bravado and meaningless BS if he was a DAC.
eta - State and municipal workers, and teachers, that have collective bargaining rights DO get to bargain all that stuff in many places, which is total BS. They work for a legal monopoly that is also a pubic utility, giving them the ability to hold it over a barrel and ass-rape it every time they want more pay and bennies is horseshit.