Page "Election" Paragraph 20

Pre-determined or fixed election dates have the advantage of fairness and predictability.

However, they tend to greatly lengthen campaigns, and make dissolving the legislature ( parliamentary system ) more problematic if the date should happen to fall at time when dissolution is inconvenient ( e. g. when war breaks out ).

Other states ( e. g., the United Kingdom ) only set maximum time in office, and the executive decides exactly when within that limit it will actually go to the polls.

In practice, this means the government remains in power for close to its full term, and choose an election date it calculates to be in its best interests ( unless something special happens, such as a motion of no-confidence ).

This calculation depends on a number of variables, such as its performance in opinion polls and the size of its majority.