<Li> Third, Article 36 (2) allows states to make optional clause declarations accepting the Court's jurisdiction . The label "compulsory" sometimes placed on Article 36 (2) jurisdiction is misleading since declarations by states are voluntary . Furthermore, many declarations contain reservations, such as exclusion from jurisdiction certain types of disputes ("ratione materia"). The principle of reciprocity may further limit jurisdiction . As of February 2011, sixty - six states had a declaration in force . Of the permanent Security Council members, only the United Kingdom has a declaration . In the Court's early years, most declarations were made by industrialized countries . Since the Nicaragua Case, declarations made by developing countries have increased, reflecting a growing confidence in the Court since the 1980s . Industrialized countries, however, have sometimes increased exclusions or removed their declarations in recent years . Examples include the United States, as mentioned previously, and Australia, which modified its declaration in 2002 to exclude disputes on maritime boundaries (most likely to prevent an impending challenge from East Timor, which gained their independence two months later). </Li> <Li> Finally, 36 (5) provides for jurisdiction on the basis of declarations made under the Permanent Court of International Justice's statute . Article 37 of the Statute similarly transfers jurisdiction under any compromissory clause in a treaty that gave jurisdiction to the PCIJ . </Li> <Li> In addition, the Court may have jurisdiction on the basis of tacit consent (forum prorogatum). In the absence of clear jurisdiction under Article 36, jurisdiction is established if the respondent accepts ICJ jurisdiction explicitly or simply pleads on the merits . The notion arose in the Corfu Channel Case (UK v Albania) (1949), in which the Court held that a letter from Albania stating that it submitted to the jurisdiction of the ICJ was sufficient to grant the court jurisdiction . </Li> <P> An advisory opinion is a function of the Court open only to specified United Nations bodies and agencies . On receiving a request, the Court decides which states and organizations might provide useful information and gives them an opportunity to present written or oral statements . Advisory opinions were intended as a means by which UN agencies could seek the Court's help in deciding complex legal issues that might fall under their respective mandates . </P>

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