Asylum Case (Colombia v Peru)

• Victor Raul Haya de la Torre, a Peruvian opposition leader, sought refuge in the Colombian Embassy in Lima following an unsuccessful rebellion
• Colombia granted him diplomatic asylum and demanded safe conduct for him to leave Peru
• Colombia invoked a regional Latin American custom permitting the asylum-granting state to unilaterally characterise the offence as political
• Peru denied any such custom existed and refused safe conduct
• Colombia relied on the Havana Convention 1928 and alleged consistent Latin American practice

1. Whether Colombia had the right under regional custom to make a unilateral and definitive qualification of the offence as political, binding on Peru as the territorial state.

• The ICJ rejected Colombia's claim
• The practice relied upon was not constant and uniform among Latin American states
• Significant discrepancies and contradictions in state practice undermined any claim of regional custom
• The burden of proof lies on the state invoking the regional custom
• Colombia failed to discharge that burden

A party relying on regional or special custom must prove that the alleged rule has been established in such a manner that it has become binding on the other party. This requires constant and uniform usage practiced by the states concerned, accepted by them as a legal obligation. The burden falls on the proponent state to demonstrate both elements.