Unions sometimes attempt to impose limitations upon the right of a member to resign. Several federal courts have held that the First Amendment protects a public employees’ right to resign union membership at any time. Some states, but not all, also have statutes that guarantee public employees the right to resign.
As a nonmember, you also have a First Amendment right not to pay any money to a union, unless you have affirmatively consented and knowingly and clearly waived your First Amendment right not to financially support a union.
The decision to resign is yours alone. In addition to not having any financial obligations to the union, as a nonmember you would not be subject to union rules and discipline. The union would have to continue to represent you fairly and without discrimination in all matters subject to collective bargaining, and you could not be denied any benefits under the labor contract with your employer because of nonmembership.
On the other hand, you would not have the right to vote on ratification of the contract or election of union officers, and there may be member-only benefits provided under the union’s constitution or bylaws that are not available to nonmembers. Since you work for the state or local government (public sector), even if there is a state law or contract between your employer and the union containing a provision requiring you to join the union or pay union fees, after resigning, you would have no obligations whatsoever to the union because that state law or forced fee contractual provision is unconstitutional. (However, if as a union member you signed a dues deduction authorization, that authorization may contain a limitation on when it can be revoked.)
If you would like to see a sample union resignation letter for public employees, click here. You should check your union’s constitution and bylaws to see if it specifies to whom a resignation must be sent.