18 SITAROPOULOS AND GIAKOUMOPOULOS v. GREECE JUDGMENT the latter was purely optional. Furthermore, the exercise of postal voting had to comply with the constitutional principle of simultaneous conduct of parliamentary elections. The Government also reiterated the reasons for requiring an enhanced two-thirds majority for enactment of the implementing legislation referred to in Article 51 § 4 of the Constitution, namely the need for political consensus in view of the considerable numbers of Greek citizens living abroad (some 3,700,000 persons compared with a population of 11,000,000 living in Greece). For instance, there were around 1,850,000 Greek citizens living in the United States and some 558,000 in Australia. Hence, according to the Government, the broadest possible consensus among the political parties was needed in order to prevent political tensions arising out of the de facto increase in the electorate. 57. The Government argued that Greek citizens who had their permanent residence abroad developed social, economic, political and cultural ties in their host country and that the main centre of their interests lay there. In addition, any comparison between Greece and other countries which had granted expatriates the right to vote from their place of residence had to take into account the specific features of each case, in particular the number of citizens living outside their country of origin, the socio-political context in each country and the electoral system in place. 58. The Government further submitted that the participation of expatriate Greeks in parliamentary elections could not be compared to the exercise of the right to vote in elections to the European Parliament. In the latter case, it was merely a matter of granting voting rights to a section of expatriate Greeks, namely those resident in member States of the European Union, an obligation arising directly out of European Union law and specifically provided for in domestic legislation. 59. To sum up, the Government pointed out that the applicants satisfied the requirements laid down by the electoral legislation for the purposes of exercising their right to vote in Greece. The issue of granting expatriates the right to vote from their place of residence fell within the margin of appreciation of the domestic authorities, who could decide how and when to grant that right. 3. The third-party intervener 60. The Hellenic League for Human Rights, established in 1953, is the oldest non-governmental organisation in Greece and a member of the International Federation for Human Rights. It noted the paradoxical situation with regard to voting rights for expatriates from their place of residence. While the right of expatriates to participate in the political decisions of the “motherland” was not disputed, the principle in question, which had acquired constitutional value, appeared to be ineffective: although ten years had elapsed since the constitutional revision of 2001, the