The Houses of Parliament are sometimes referred to as ‘houses of debate’. It is important to understand the role of debate in our system of government.
When legislation is passed Members of Parliament debate the merits or shortcomings of the Bill before the House. Despite the fact that generally political party allegiances may decide the voting outcomes of many pieces of legislation, there are times when rigorous and robust debate may convince Members to change their expected voting intentions. This is particularly so when a government does not have a large majority or when party disciplines on voting do not apply (such as with 'conscience' votes on certain issues).
Debate is also important in the Committee stage of a Bill, when legislation can be amended and a compromise might be needed to ensure the passage of legislation.
Debate in Parliament may be used as a tactic to criticise a party or individual member or to defend a party or member from criticism. Given the robust nature of such exchanges, it is not surprising that parliamentary debate is sometimes heated. Despite these occasions, much legislation is passed in Parliament with the support of both the Government and the Opposition.