Smith sought to involve Abel Muzorewa and Ndabaningi Sithole, Rhodesia's "internal" black leaders, and even Joshua Nkomo, the Matabele leader and most prestigious of the insurgent "external" black politicians, in the search for a solution. After a 1976 conference promoted by US Secretary of State Henry Kissinger failed, Smith played his last card: an "internal" settlement which was signed on 4 March 1978 with Sithole and Muzorewa.
By now Nkomo and Robert Mugabe, nationalist leader of the majority Shona, had forged the Patriotic Front, a ZANU-ZAPU alliance. The ‘terrorists’ were wreaking havoc, and white emigration was costing the security forces the equivalent of a battalion of fighting men a month. The end was only a matter of time.
On 1 June 1979, after 15 years as Prime Minister, Smith was succeeded by Bishop Muzorewa as interim prime minister of a government of national unity. Sanctions were lifted ahead of a planned all-party conference at Lancaster House in London.