meetings, in their publications and in the course of other trade union activities.”51 In this regard, it has affirmed that “The right to express opinions through the press or otherwise is an essential aspect of trade union rights,” and that this right “should in no way differ from the right to express opinions in exclusively occupational or trade union journals.”52 The Committee underscored that “The right of workers’ and employers’ organizations to express their views in the press or through other media is one of the essential elements of freedom of association; consequently the authorities should refrain from unduly impeding its lawful exercise.”53 83. The European Court of Human Rights has also acknowledged in its case law that the right to freedom of expression protects the right of union members to express their demands to their employers, for purposes of improving their working conditions.54 According to the Court, the freedom of expression of labor unions and their leaders is an essential means of action, without which they would lose their effectiveness and their raison d'être. Accordingly, the national authorities are obligated to ensure that the imposition of disproportionate sanctions do not have a chilling effect on the right of union representatives to express and defend workers’ interests.55 84. As explained below, the right to freedom of expression may be subject to specific limitations in the context of labor-related matters. It is not an absolute right, and as such may be restricted to protect other relevant legal interests in accordance with Article 13.2 of the American Convention. 85. The case law of the Inter-American Commission and Court has consistently held that the establishment of limitations to the right to freedom of thought and expression must be exceptional in nature, and in order to be admissible must be subject to three basic conditions set forth in Article 13.2 of the Convention: (a) the limitation must be clearly and precisely defined in a substantive and procedural law; (b) it must pursue objectives authorized by the American Convention; and (c) it must be necessary in a democratic society for the attainment of the aims pursued, suitable for accomplishing the intended objective, and strictly proportional to the aims pursued. 86. According to Article 13.2 of the American Convention, all limitations on freedom of expression must be established by law. The Inter-American Court has repeatedly explained that it must be a law that establishes, in advance, and in the clearest and most precise terms possible, the grounds for the subsequent imposition of liability to which the exercise of freedom of expression may be subject.56 The Court has therefore held that vague or ambiguous legal provisions granting very broad discretion to the authorities are incompatible with the American Convention, because they can be used as the basis for arbitrary acts that amount to prior censorship or that impose disproportionate liabilities for the use of speech protected by the Convention.57 51 ILO. Freedom of Association. Digest of decisions and principles of the Freedom of Association Committee of the Governing Body of the ILO. Fifth (Revised) Edition (2006). Para. 154. 52 ILO. Freedom of Association. Digest of decisions and principles of the Freedom of Association Committee of the Governing Body of the ILO. Fifth (Revised) Edition (2006). Paras. 155 - 158. 53 ILO. Freedom of Association. Digest of decisions and principles of the Freedom of Association Committee of the Governing Body of the ILO. Fifth (Revised) Edition (2006). Para. 159. 54 ECHR, Case of Vereinigung demokratischer Soldaten Österreichs and Gubi v. Austria (Application No. 15153/89). Judgment of 19 December 1994; European Court of Human Rights. Case of Palomo Sánchez and Others v. Spain (Applications Nos. 28955/06, 28957/06, 28959/06 and 28964/06). Judgment of September 12, 2012. 55ECHR, Case of Palomo Sánchez and Others v. Spain (Applications Nos. 28955/06, 28957/06, 28959/06 and 28964/06). Judgment of September 12, 2012, para. 56. 56 I/A Court H.R., Compulsory Membership in an Association Prescribed by Law for the Practice of Journalism (Arts. 13 and 29 American Convention on Human Rights). Advisory Opinion OC-5/85 of November 13, 1985. Series A No. 5, paras. 39-40; I/A Court H.R., Case of Palamara Iribarne v. Chile. Judgment of November 22, 2005. Series C No. 135, para. 79; I/A Court H.R., Case of Herrera Ulloa v. Costa Rica. Judgment of July 2, 2004. Series C No. 107, para. 120; I/A Court H.R., Case of Tristán Donoso v. Panama. Preliminary Objection, Merits, Reparations and Costs. Judgment of January 27, 2009. Series C No. 193, para. 117; IACHR. Annual Report 1994. Chapter V: Report on the Compatibility of “Desacato” Laws with the American Convention on Human Rights. Title IV. OEA/Ser. L/V/II.88. doc. 9 rev. February 17, 1995; IACHR. Report No. 11/96. Case No. 11.230. Francisco Martorell. Chile. May 3, 1996, para. 55; CIDH. Arguments before the Inter-American Court in the Case of Ricardo Canese v. Paraguay. Transcribed in: I/A Court H.R., Case of Ricardo Canese v. Paraguay. Judgment of August 31, 2004. Series C No. 111, para. 72. a). 57 See IACHR, Report of the Office of the Special Rapporteur for Freedom of Expression 2009, OEA/Ser.L/V/II.Doc. 51, December 30, 2009, Chapter III, para. 71. 17