Yellow dog contracts are agreements between an employer and employee in which, often as a precondition to being hired, the employee agrees not to become a labor union member or act in collaboration with other employees. There are both federal and state statutes outlawing yellow dog contracts. Additionally, while early Supreme Court cases have upheld such contracts on the basis of respecting parties' liberty to negotiate and agree to their own employment terms, the Court eventually sided with the constitutional principle of federalism, allowing states to legislate their own commercial and employment affairs. In turn, states have outlawed such practices out of recognition of the value of unions (i.e., in providing fair working conditions) and such contracts being harmful to public welfare.
For example, New York's labor laws deem it an unfair labor practice to require an employee, as a condition to employment, to refrain from joining a union. Under federal law, the Norris-La Guardia Act of 1932 expressly makes any yellow dog contract unenforceable in any court. Section 7 of the National Labors Relations Act further grants workers the right to form unions without employer interference.
[Last updated in April of 2022 by the Wex Definitions Team]