Public employee unions may only require a pro rata share of dues to be used for legitimate costs of union benefits, such as collective bargaining. If an employee (including a teacher) objects to dues being spent on political or ideological causes, that employee has a free speech right not to be compelled to support that portion of union activities. Teachers must be permitted to redirect that portion of their union dues that would be used to support objectionable ideological or political causes. Teachers may also elect to join an alternative teacher’s organization.
—Keeping Christ in America’s Public Schools, Gibbs & Gibbs, 2008d