Guinea-Bissau’s election on Sunday to replace its slain president will be a test for West Africa’s ability to stop the retreat of democracy as well as for a state destabilised by drug smugglers and army rivalries. The fact the vote is happening at all is something of an achievement within four months of President Joao Bernardo “Nino” Vieira being shot dead and after the killing of a top contender and another senior politician during the campaign.