paft: as human beings, principals might occasionally abuse their position?
w: and you think a union is going to prevent this? thats naivete paft.

Unions in combination with state laws? Yes, they will. Unions already shown themselves to be an effective force for improving the lot of workers. As you've already admitted.

pft: And what forces campaigned for those labor laws?
w: unions, back when they served a purpose.

And in the absence of unions, what's to prevent those laws from being repealed, overridden, or just flouted?