As the guarantor of the Arusha agreement that brought political peace to Burundi, South Africa has again been called on to provide leadership. Rival groups of the Burundi military are battling it out on the streets of Bujumbura following protests by citizens against President Pierre Nkurunziza's intention to stand for a third term.Our deputy president, Cyril Ramaphosa, is in Dar es Salaam, Tanzania, to help broker a peace deal.This country has a duty to intervene and help restore peace in Burundi, continuing the work started by Mwalimu Julius Nyerere and taken forward by Nelson Mandela.What we see on the streets of Bujumbura today goes against the efforts of those leaders to bring stability to the continent.Though no country can dictate to the Burundians, it is important to hammer home to Nkurunziza the importance of respecting the Arusha agreement and the constitution that came out of it.Leaders must respect the will of the people and desist from manipulating the system to cling to power.It is of concern that among those broking peace in Dar es Salaam are other leaders trying to extend their term of office unconstitutionally.For Africa to progress, its leaders must lead by example and build institutions that not only promote democracy but empower citizens to have a say in how they are governed.We fully agree with Ramaphosa that Burundi today is undermining democracy and stability, soiling the legacies of Nyerere and Mandela.South Africa should insist that the leaders in Burundi settle their differences and deal with the politics at the centre of this conflict.Nkurunziza cannot remain deaf to the calls for him to respect his country's constitution.The Arusha agreement was clear that there should be peace, democracy and stability in Burundi...