Right-to-work laws are state laws that prohibit both the closed and union shop. A right to work law secures the right of employees to decide for themselves whether or not to join or financially support a union. However, employees who work in the railway or airline industries are not protected by a right to work law, and employees who work on a federal enclave may not be.
Under federal labor law and state right to work laws, which exist in slightly less than half of the states, you have the right to resign from membership in a union at any time. If you resign from membership, you may not be able to participate in union elections or meetings, vote in collective bargaining ratification elections, or participate in other "internal" union activities. If you resign, you cannot be disciplined by the union for any post-resignation conduct.
If you resign from union membership, you are still fully covered by the collective bargaining agreement that was negotiated between your employer and the union, and the union remains obligated to represent you. Any benefits that are provided to you by your employer pursuant to the collective bargaining agreement (e.g., wages, seniority, vacations, pension, health insurance) will not be affected by your resignation. Howver, the union may exclude you from some "members-only" benefits. Although you may resign from union membership at anytime, you may be limited to a specific "window period" before you are able to end any automatic dues deductions.