Pope Francis began a nine-day tour of Cuba and the United States yesterday where he will see both the benefits and complexities of a fast-evolving detente between the old Cold War foes that he helped broker. Better sensitised to the issue than predecessors because of his Latin American roots, the 78-year-old Argentine pontiff facilitated a back channel for talks and sent missives to Presidents Raul Castro and Barack Obama in 2014. That bore fruit with this year's re-establishment of diplomatic ties and the easing of some travel and trade restrictions though a half-century-old economic embargo is still in place, only removable by the US Congress.