The National Right to Work Legal Defense Foundation argued a claim against the Illinois's Public Labor Relations Act, on the ground that it violated the First Amendment.

The trade union was SEIU Healthcare Illinois & Indiana, which bargained with the state, after it was awarded exclusive representation of the caregivers following a card check election in 2003.

[5] The Court ruled that the workers could not be compelled to join the union since they were not fully-fledged state employees, as they are hired or fired by individual patients even if they are paid by Medicaid.

The ruling did not invalidate compulsory union membership for the larger population of public employees, but Justice Samuel Alito's majority opinion argued that Abood v. Detroit Board of Education was erroneously decided.

[8] The majority's opinion in Harris v. Quinn was largely condemned by labor unions, worker rights organizations [citation needed], and the Democratic Party for overturning established precedent since the Taft-Hartley Act of 1947.