In a lawsuit against three Indiana government officials, a labor union alleged on Wednesday that its constitutional rights under the Thirteenth Amendment — which outlawed “slavery” and “involuntary servitude” — are violated whenever its members are forced to work alongside nonunion employees.

The International Union of Operating Engineers, whose members work as heavy equipment operators, mechanics and construction surveyors, sued Indiana’s governor, attorney general, and labor commissioner in February, alleging that the state’s “right to work” law is unconstitutional.

Indiana’s law prohibits employers from making union membership a condition of getting or keeping a job. The union’s February lawsuit claimed the law violated its members’ Fourteenth Amendment guarantee of “equal protection” under the law.

But an amended complaint filed on Wednesday added a Thirteenth Amendment claim as well. The new lawsuit suggests that when nonunion employees earn higher salaries and better benefits because of the union’s negotiation on behalf of its members, the union has been forced to work for those nonunion employees for free.

And being forced to work without compensation, the union suggested in its revised lawsuit, is slavery.

“In this case, the Defendants have exacted compulsory service and/or involuntary servitude from the Union through the combination of the passage of the Right to Work law and the existing federal requirement of the duty of fair representation,” the amended complaint reads.

“Through these laws, the Union is compelled to furnish services to all persons in bargaining units that it represents, but it may not require payment for those services because of the Right to Work law. The statute also requires dues-paying union members to work alongside non-union personnel, and that is compulsory service and/or involuntary servitude within the meaning of the Thirteenth Amendment.”

Mackinac Center for Public Policy senior legal analyst Patrick Wright said on Friday that the union’s legal argument “expands the definition of chutzpah.”

“Compulsory membership and coerced dues and fees are the hallmarks of the union movement, yet they claim that giving workers more choice is an act of enslavement.”

Competitive Enterprise Institute labor policy counsel Vincent Vernuccio told the Mackinac Center that “it’s insulting to the great civil rights leaders to compare the new forced unionism movement to what civil rights leaders went through in the 1950s and 1960s.”

Including Indiana, 23 U.S. states have “right to work” laws in force.

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SEE PAGE 26: Read the union’s “slavery” lawsuit against Indiana’s right-to-work law