The Michigan Education Association has such a monopolistic stranglehold on unionizing public school teachers that most teachers don't even know that they can resign their union membership and become an "agency fee payer." The MEA has worked hard to limit teachers' rights to do just this, and currently the month of August is the only timeframe the union allows for members to resign.
Why would a teacher want to do this? A common reason for many teachers is objecting to the fact that their dues fund political activities that they disagree with either politically or ideologically. Both the MEA and its national affiliate, the National Education Association, use dues revenue to advocate for 360 different issues as part of their political agendas. The MEA and NEA overwhelmingly side with Democrats on political issues, and the vast majority of their political spending ends up in the coffers of that same political party.
Another reason teachers resign their membership is that it saves them money. Instead of forking over what the union says it needs, teachers are only required to pay fees equal to the amount required to provide representation services. A 1988 United State Supreme Court decision defined and upheld these rights, and they're known now as an employee's "Beck rights."
Some teachers object to union membership on religious grounds. Title VII of the Civil Rights Act affords public school teachers this right, and resigning under these terms allows teachers to redirect all of their mandatory union fees to an agreed-upon charity.
In order to become an "agency fee payer," teachers simply need to write a letter to their local union and announce that they are resigning their membership. This pamphlet provides a sample resignation letter as well as answers to a series of common questions about the procedure. (Teachers often have a lot of questions because in some cases the language in their contracts or messages they hear from union officials make it seem as if they'll never be able to get out from under the burden of paying full mandatory union dues.)
The window of opportunity to resign their union membership is extremely small, so speedy action is required if teachers should choose to exercise these rights.