Just how do political parties co-manage a government ministry?

A1987 agreement marking the merger between President Robert Mugabe's Zimbabwe African National Union (ZANU) and the late Joshua Nkomo's Zimbabwe African People's Union (ZAPU) handed control of that country's home affairs ministry to ZAPU in perpetuity. Mugabe now wants to entrench this arrangement in the proposed power-sharing government between his party and Morgan Tsvangirai's Movement for Democratic Change (MDC) (Mail & Guardian 30 October-6 November 2008).