Several things tend to get lost in the discussion re: part-timers.
1. The Teamsters allowing UPS to rely on a PT workforce and create/maintain a tremendous pay gap between FT and PT workers divided the union. Now we have a whole faction of drivers thinking they are "worth more" than the package handling peons. That's a sure sign of rot in the brotherhood.
While I agree that PTers must get more involved, as well as organize themselves and make serious demands ...
2. the same could be said about FTers. In my experience most FTers treat the union as a third-party service and aren't willing to sacrifice the time necessary to strenghen the union. I know few who even bother to read the contract, let alone enforce it. And those of us who get involved often find ourselves dealing with complacent officers who are quick to make excuses for the company and who sit quietly in the office or at local hearings while management openly insults and tries to intimidate Teamsters.
3. The PT workforce has atrociously high turnover. Management calls it churn. That's what the company wants. It is next to impossible to make a strong, well-organized union under these conditions. People are constantly coming and going. There's no time to build either knowledge or trust.