Brazil's president Dilma Rousseff is battling for political survival. She could be facing impeachment over alleged economic mismanagement and widespread corruption, and Brazil could be spiralling into the worst economic recession for decades. Is the country teetering on the brink of a major political and economic crisis? Zeinab Badawi speaks to Celso Amorim, who served the last three presidents of Brazil, first as a long-time foreign minister and then as defence minister until January 2015.