A historic meeting of Latin America's leaders, to be attended by Barack Obama, will hear serving heads of state admit that the war on drugs has been a failure and that alternatives to prohibition must now be found. The Summit of the Americas, to be held in Cartagena, Colombia is being seen by foreign policy experts as a watershed moment in the redrafting of global drugs policy in favour of a more nuanced and liberalised approach. Otto Pérez Molina, the president of Guatemala, is pushing his fellow Latin American leaders to use the summit to endorse a new regional security plan that would see an end to prohibition.