In Northern Ireland, executive power is shared among political parties, whether any single party has won a majority of seats in the Assembly or not.
This is unlike the system in Westminster and the devolved institutions in Scotland and Wales, where executive power is shared only when parties are forced into
Ministerial positions in the Northern Ireland executive are allocated according to the
a type of proportional representation.
The idea of power-sharing as a solution to Northern Ireland's political problems originated with John Whyte, of Queen's University Belfast, who argued that the Westminster model would be ineffective and potentially unjust in Northern Ireland.
In 1972, the Sunningdale Agreement paved the way for the first power-sharing government. As a result of unionist opposition and power strikes organised by the Ulster Workers' Council, the resulting government collapsed five months after its formation in 1974.
Subsequent attempts at power-sharing foundered.
But in 1998, the Good Friday Agreement brought the modern Assembly into being and introduced the D'Hondt system to distribute government posts.
Following the 2006 St Andrews Agreement all the major political parties agreed to participate in the current power-sharing government.