The obligation imposed on a parliamentarian to take an oath making a reference to religion before taking up its office constitutes a breach of Article 9 of the ECHR.
Art. 9 ECHR
1. Freedom of thought, conscience and religion is one of the foundations of a ‘democratic society’ within the meaning of the Convention. It is, in its religious dimension, one of the most vital elements that go to make up the identity of believers and their conception of life, but it is also a precious asset for atheists, agnostics, sceptics and the unconcerned. The pluralism indissociable from a democratic society, which has been dearly won over the centuries, depends on it. Freedom of religion also entails, inter alia, freedom to hold or not to hold religious beliefs and to practise or not to practise a religion.
2. The obligation imposed on representatives of the people to take an oath with a reference to religion is equivalent to requiring them to swear allegiance to a particular religious faith. This measure is not necessary in a democratic society and constitutes a breach of article 9 of the ECHR.
(The applicants had been elected to the Great General Council of San Marino and, before they assumed their office, they were required to take an oath on the Holy Gospels, as required by the law then in force. The parliamentarians finally resolved to take the oath, but they alleged a violation of their right to freedom of religion. The Court notes that it would be contradictory to impose the performance of an act of religious content on subjects who act in the exercise of a mandate intended to represent the different points of view of society)
The judgment of the Grand Chamber is a leading case, which for the first time declares the obligation imposed by a State to perform an act of a religious nature incompatible with Article 9 of the Convention.