Informal vote

In voting, a ballot is considered spoilt, spoiled, void, null, informal, invalid, or stray if a law declares or an election authority determines that it is invalid and thus not included in the vote count. This may occur accidentally or deliberately. The total number of spoilt votes in a United States election has been called the residual vote. In Australia, such votes are generally referred to as informal votes, and in Canada they are referred to as rejected votes.

In some jurisdictions, spoilt votes are counted and reported.

A ballot may be spoiled in a number of ways, including:

As an example, UK law specifically precludes ballots "on which votes are given for more candidates than the voter is entitled to vote for", "on which anything is written or marked by which the voter can be identified" or "which [are] unmarked or void for uncertainty".

If a voter makes a mistake while completing a ballot, it may be possible to cancel it and start the voting process again. In the United States, cancelled physical ballots may be called "spoiled ballots", as distinct from an "invalid vote" which has been cast.

In Canada, a spoiled ballot is one that has been handled by an elector in such a manner that it is ruined beyond use, or that the deputy returning officer finds soiled or improperly printed. The spoiled ballot is not placed in the ballot box, but rather is marked as spoiled by the deputy returning officer and set aside. The elector is given another ballot. A 'rejected ballot' is one which cannot be counted due to improper marking by the voter. Examples of this are ballots which have more than one mark, the intent of the voter cannot be ascertained, or the voter can be identified by their mark.

In many jurisdictions, if multiple elections or referenda are held simultaneously, then there may be separate physical ballots for each, which may be printed on different-colored paper and posted into separate ballot boxes. In the United States, a single physical ballot is often used to record multiple separate votes. In such cases one can distinguish an "invalid ballot", where all votes on the ballot are rendered invalid, from a "partially valid" ballot, with some votes are valid and others invalid.

A voter may deliberately spoil a vote, for example as a protest vote, especially in compulsory voting jurisdictions, to show disapproval of the candidates standing whilst still taking part in the electoral process. Intentionally spoiling someone else's ballot before or during tabulation is an electoral fraud.

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