The range of topics that cover the side letters is wide. In some cases, letters of appeal have promoted national labour law policy. In the United States, for example, a subsidiary letter guaranteeing the neutrality of employers in union elections in newly acquired factories, subsidiaries or departments led to federal action on the legality of the agreement in 2002 and a major decision by the National Labor Relations Board, which revised federal labour policy in 2007. T52  Y lo sorprendente es que ese breve documento, que resuelve las mes delicadas controversias, las “side letters,” se redactan sobre la marcha, en el éltimo momento, con sus redactores normalmente ya mermados, en unas lineas … y a veces, con frecuencia, containen afirmaciones delicadas, que se aproximan a la raya que separa lo lecito de lo illécito, a la raya que separa lo civil de lo penal.- According to contract law, a letter has the same force as the underlying contract.  However, the courts may invalidate the letters in opposition to the main collective agreement.  The conditions of the CBA govern the interpretation of decical letters. In the United States, several appelor courts have decided that the parties must use the dispute resolution mechanism of the underlying collective agreement (in these cases, an arbitration procedure) to resolve the dispute in disputes where the letters do not include dispute resolution procedures.    In Australia, letters of application are becoming more frequent because of changes to federal labour law by the WorkChoices Act. WorkChoices limits collective agreements that parties can declare to enforce labour tribunals and also requires that CBAs be strictly limited to labour-related issues.
The inclusion of smaller, non-workplace clauses (e.g. B, the removal of taxes) can no longer make a CBA enforceable. In response, many unions and employers use secondary letters to reach agreement on employment issues, and do not register these secondary letters with the federal government, relying on the common law to enforce the letters.  Appendix 3 of the subsidiary agreement can only be amended by a written agreement between the parties. Esa variedad de significados nos da la pauta para su correcta traduccién en contexto.