For example, during the Iran hostage crisis, Iran refused to participate in a case brought by the US based on a compromissory clause contained in the Vienna Convention on Diplomatic Relations and did not comply with the judgment.[27] Since the 1970s, the use of such clauses has declined. Many modern treaties set out their own dispute resolution regime, often based on forms of arbitration.[28] 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.