"If an employer reviews a document reflecting the agreements reached in collective bargaining and the union surreptitiously substitutes a materially different contract document before both sides execute it, we think it clear that there has been a fraud in the execution of the contract and that the agreement reflected in the executed document is void ab initio and unenforceable by the union."
"A contract that is void ab initio is a nullity, for it is based on a promise for breach of which the law neither gives a remedy nor otherwise recognizes a duty of performance by the promisor."
