This right hasn't always existed; for most of our history public workers were not permitted to form unions. Most sources suggest permission began in 1958 with Mayor Robert Wagner of New York City, spread throughout the states, and was extended to federal workers by JFK in 1962.
This history suggests state governments should be able to roll back unionization rights for public workers state by state, until only blue states are left with it. Getting to the point where we can deny bargaining rights to federal workers would require a GOP majority of both houses of Congress plus a president all willing to go along.
This situation has only existed during four years since the end of World War II - the middle four of George W. Bush's eight years. In other words, it is a desirable condition but one not easy to achieve nor one that has often existed in recent times. And, it should be noted, during that four year period the votes existed but not the will or interest, unfortunately.
