However, agreements between States and international organizations or between international organizations themselves are governed by the 1986 Vienna Convention on the Law of Treaties between States and International Organizations or between International Organizations when it enters into force. In addition, the provisions of the Convention among the Members of the State continue to apply in treaties between States and international organizations.  The Convention does not apply to un written agreements.  The Convention codifies several foundations of contemporary international law. It defines a treaty as “an international agreement concluded in writing between States and subject to international law” and reaffirms that “each State has the capacity to conclude treaties”. Article I limits the application of the Convention to written treaties between States and excludes treaties concluded between States and international organizations or international organizations themselves. Article 26 defines pacta sunt servanda, article 53 proclaims the peremptory norm and article 62 proclaims the fundamental change of circumstances. The Convention applies only to treaties concluded after its establishment and between States and therefore does not apply to agreements between States and international organizations or between international organizations themselves, but if any of its rules are independently binding on those organizations, they remain so.  The VCLT applies to contracts between States within an intergovernmental organization.  In order to avoid duplication between the level of standardisation and the European level, to the benefit of standardisation participants and users of standards, and to improve the effectiveness of standardisation at European and international level, CEN and CENELEC have signed agreements with their respective international partners, the International Organisation for Standardisation (ISO) and the International Electrotechnical Commission (IEC), establishing the rules of cooperation.
The Vienna Agreement, signed in 1991 between CEN and ISO, recognises the primacy of international standards and aims to ensure that standards are recognised simultaneously at international and European level by improving the exchange of information and mutual representation at meetings. Either CEN or ISO take the lead in the development of a new standard and the relevant documents must be submitted for simultaneous approval. ISO members can thus influence the content of the CEN standard and vice versa. Around 31% of CEN standards are developed under the Vienna Agreement. Nevertheless, the Vienna Agreement allows CEN or ISO to carry out standardisation activities on the same subject if deemed necessary. The Joint ISO-CEN Coordinating Group of the Technical Boards has an important strategic role to play in monitoring the implementation of the Vienna Agreement and advising the CEN Higher Technical Council and the ISO Technical Management Committee on all matters related to the Vienna Agreement, i.e. the need for revisions. In September 2001, a revised version (version 3.3) of the Vienn Agreement was published, in which the agreement itself was reduced to the essential principles of cooperation BETWEEN ISO and CEN. Overall, the current version gives priority to international standardization and gives ISO management greater importance than previous versions. For example, EN-ISO standards can only be revised under the guidance of ISO, regardless of their origin. In 1996, CENELEC and the IEC signed the Dresden Agreement in order to create the necessary framework for an intensive consensus process between European and international standardization activities in the electricity sector.
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