SAVICKIS AND OTHERS v. LATVIA JUDGMENT reasons in the instant case, especially in the light of the expanded reasoning adduced by the Constitutional Court in its judgment of 17 February 2011. 203. The Court agrees with the Constitutional Court that upon the restoration of its independence Latvia was not obliged to assume the responsibilities of the USSR. Having undergone unlawful occupation and subsequent annexation, a State is not required to assume the public-law obligations accrued by the illegally established public authorities of the occupying or annexing power. Latvia was neither automatically bound by such obligations based on the Soviet period nor obliged to undertake obligations emanating from obligations of the occupying or annexing State. The Court observes, however, that once Latvia had put in place a system of occupational retirement pensions in 1996 which allowed for periods of employment accrued outside its territory to be counted towards the pension for Latvian nationals, it was bound, as from the date on which the Convention entered into force in respect of Latvia (that is, 27 June 1997), to comply with Article 14 taken in conjunction with Article 1 of Protocol No. 1. (β) Considerations relating to the scope of the margin of appreciation 204. Although an overview of the relevant general principles deriving from the Court’s case-law is presented above (see paragraphs 183-185), and given that the margin of appreciation to be accorded to the competent national authorities will vary in the light of the nature of the issues and the seriousness of the interests at stake, the Court finds it important at the outset to proceed with a closer analysis of the various relevant considerations to be taken into account when determining the appropriate scope of the margin of appreciation in the specific circumstances of the present case. In this regard, the Court observes the following. 205. The Court has repeatedly held, on the one hand, that in the field of social security and fiscal matters the margin of appreciation enjoyed by States must be wide (see paragraph 184 above). On the other hand, it has also repeatedly held that only “very weighty reasons” could justify a difference in treatment based exclusively on the grounds of nationality for the purposes of Article 14 of the Convention, thus indicating a narrow margin and strict scrutiny by the Court (see Gaygusuz, cited above, § 42; Andrejeva, cited above, § 87; and Ribać, cited above, § 53). In Stec (cited above, § 52) the Court set out the requirement of “very weighty reasons”, followed by the principle of “wide margin” in general measures of economic or social strategy, including a reference to the test of “manifestly without reasonable foundation” (see also, albeit in the context of “other status”, Stummer, cited above, §§ 101 and 109). 206. That being stated, the Court notes, firstly, that while the scope of the margin of appreciation clearly cannot be the same as regards the adoption of general measures of economic and social policy and as regards the introduction, in that context, of differences in treatment based solely on 68