The United Nations Security Council has voted to sanction the leaders of Congo's M23 rebel force that has occupied the eastern Congolese city of Goma as UN peacekeepers stood by without resisting. President Joseph Kabila said war had been imposed on his country — and urged the entire population to defend its sovereignty. Jason Stearns, the director of the Rift Valley Institute's Usalama Project, which researches armed groups in the eastern Congo talked to BBC Newsday.