The deceptively simple zipper clause included in the labor contract is profoundly powerful in its effects, or would be so if the legal exceptions of such a clause were not so prohibitive of its seeming intent. The clause is not especially complex, and means exactly what it says -- except for instances explicitly specified by he contract, no further bargaining is needed or can be required until the termination/expiration of the contract as "all the bargainable issues for the term thereof" have been definitively addressed by the contract. When both parties (i.e. labor and management) sign this contract, it is intended to mean that both parties are agreeing that all bargainable issues have been dealt with, and that therefore no more bargaining is necessary.
In reality, however, the full scope of the clauses' stated powers cannot be enforced due to existing legal requirements enforcing mandatory bargaining on certain labor issues. The zipper clause, that is, cannot prevent either labor or management from seeking or insisting on bargaining over an area that specifically requires bargaining between the two parties under U.S. labor law. Even if the labor contract grants unilateral authority to one or the other of the parties in regards to a particular issue, any action taken that affects an area for which collective bargaining is mandated must be agreed upon by both labor and management. In this scenario, management's interpretation of the contract suggests that this contract supersedes law and legal precedent, claiming that the unilateral power granted it in the contract and the zipper clause both separately grant them absolute authority to make the new rules.
Had these rules not encroached upon grounds of mandatory bargaining, this reading of the contract would have been applicable. However, given that bonuses and incentive pay are areas of employment compensation in which decisions must be reached via collective bargaining, the issue of increased wages for achieving perfect attendance is something that must be negotiated. As the union cannot actually force management to pay any such bonus, when the contract still in effect did not provide for one, it does not seem especially advantageous for them to press the issue at this point, but they certainly have a legal right to. The new work rules specifically use the word "bonus" to describe the additional pay, which is clearly a form of incentive pay as well; management did not even make an effort to circumvent the law through a manipulation of language (though apparently through arrogance rather than forthrightness).
The testing of employees is also considered a condition of employment worthy of mandatory collective bargaining, so management would again be in the wrong regarding this rule. Depending on the state of operation, such a rule's very legality might be in question; at the least, mandatory drug tests have consistently been seen as an invasion of privacy in many occupations, and bargaining n this point is not only legally mandatory but provides better protection for the employer in producing legally indisputable results in the case of a positive test related to an accident and/or injury. The fact that they would attempt to implement this new policy without prior notice or negotiation is evidence of bad faith bargaining on management's part.
The implementation of the new system of bonuses does not itself constitute an instance of bad faith bargaining, as it was not a reduction of current bonuses and in no way had an adverse effect on the employees. Their refusal to meet for bargaining regarding the issue, however, is a violation of good faith principles. Thus, both on their original implementation of the drug testing rule and in their refusal to meet for bargaining on both issues displays bad faith bargaining on the part of the management. In this instance, suit could be filed in federal courts after the filing of an official complaint with the National Labor Relations Board. Repeated attempts to bring management to bargaining throughout the process would be advantageous, however, as the federal courts have limited power and at best will most likely simply force management to the bargaining table, without imposing any other restrictions or conferring advantages to either party.