Whether a party commits an unfair labor practice by insisting to impasse on a lawful proposal that is outside the mandatory subjects of collective bargaining.
Holding
Yes. A party may propose and voluntarily bargain over a lawful permissive subject, but it may not insist on that subject as a condition of reaching an agreement.
Reasoning
Sections 8(a)(5) and 8(d) require an employer and the employees' representative to bargain in good faith about “wages, hours, and other terms and conditions of employment.” Within that mandatory sphere, neither side must accept a proposal or make a concession. Outside that sphere, however, either side remains free to bargain or decline to bargain over a matter voluntarily.
The company's good faith on mandatory subjects did not permit it to withhold agreement unless the union accepted nonmandatory proposals. Insistence to impasse on a permissive subject effectively obstructs agreement on the subjects Congress made mandatory, and therefore amounts in substance to a refusal to bargain about those mandatory subjects.
The Court stressed the distinction between proposing a clause and insisting upon it. Both disputed clauses were lawful and could have been enforced if the unions had voluntarily agreed to them. Their legality alone, however, did not make them mandatory bargaining subjects or allow the company to demand them as the price of any contract.