Abood v. Detroit Board of Education, 431 U.S. 209 (1977), was a US labor law case where the United States Supreme Court upheld the maintaining of a union shop in a public workplace.

The Court found, [The] notion that an individual should be free to believe as he will, and that, in a free society, one's beliefs should be shaped by his mind and his conscience, rather than coerced by the State ... thus prohibit[s] the appellees from requiring any of the appellants to contribute to the support of an ideological cause he may oppose as a condition of holding a job as a public school teacher ... the Constitution requires ... that such [political union] expenditures be financed from charges, dues, or assessments paid by employees who do not object to advancing those ideas and who are not coerced into doing so against their will by the threat of loss of governmental employment.

[6]Thus, in the United States' public sector, employees of the employer are entitled to not be members of the union, but they can be required to pay the documented costs of contract administration and negotiation.

If they object, typically such a determination is submitted for hearing to a neutral arbitrator who will take evidence and render a final and binding decision as to the propriety of the fees assessed.

[7][8] Since Justice Samuel Alito's confirmation to the Supreme Court in 2006, anti-union groups have looked to challenge the decision of Abood by arguing that the inherent activities of a public section union including political campaigning that make it difficult to separate the use of non-member dues.