A majority union isn't a kind of contract. It represents all workers in a bargaining unit, even workers who voted against it. In theory, this simplifies negotiations and helps make sure all workers are fairly represented.

Some union supporters worry that allowing minority unions would weaken established unions. Union opponents have focused on passing "right to work" laws, which require majority unions to represent non-members for free. The status quo probably makes unions stronger in pro-union states and weaker in anti-union states.