Crossing the floor

In politics, crossing the floor is when a politician changes their allegiance or votes against their party in a Westminster system parliament. Crossing the floor may be voting against the approved party lines, or changing to a second party after being elected to a first party. While these practices are legally permissible, crossing the floor can lead to controversy and media attention. As well, voting against party lines may lead to consequences such as losing a position (e.g., as minister or a portfolio critic) or being ejected from the party caucus.

The term originates from the British House of Commons, which is configured with the Government and Opposition facing each other on rows of benches. An MP who switched parties would literally need to cross the floor. A notable example of the latter is Winston Churchill, who crossed the floor from the Conservatives to the Liberals in 1904, before later crossing back in 1924.

The term has passed into general use in other Westminster parliamentary democracies (such as Canada, Australia, New Zealand and South Africa) even if many of these countries have semicircular or horseshoe-shaped debating chambers and mechanisms for voting without Members of Parliament leaving their seats. In most countries, it is most often used to describe members of the government party or parties who defect and vote with the opposition against some piece of government-sponsored legislation, but that usage is not widespread in Canada, where the term's usage is restricted to the original definition.

Most political parties let their members have a free vote on some matters of personal conscience.

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