Smith was by now in the twilight of his career, but his outspoken, confrontational stance continued to irritate the ZANU–PF government. He was declared a "fifth columnist" by the Information Minister Nathan Shamuyarira in February 1987 after he advised a group of South African businessmen that they could survive economic sanctions if white South Africans stood together. Three months later, after he was suspended from the Zimbabwean parliament for a year over his comments in South Africa and criticism of ZANU–PF, he resigned as leader of the CAZ. His four decades as an MP formally ended in September 1987 when, as allowed under the Lancaster House terms, ZANU–PF scrapped the white seats amid sweeping constitutional reforms. The office of Prime Minister was abolished in October; Mugabe became the country's first executive President two months later. Mugabe and Nkomo signed a unity accord at the same time, merging ZAPU into ZANU–PF with the stated goal of a Marxist–Leninist one-party state.