Independence of Smith-dominated alternatives

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Independence of Smith-dominated alternatives (ISDA, also known as Smith-IIA) is a voting system criterion which says that the winner of an election should not be affected by candidates who are not in the Smith set.^[1]

Another way of defining ISDA is to say that adding a new candidate should not change the winner of an election, unless that new candidate would beats the original winner, either directly or indirectly (by beating a candidate who beats a candidate who... who beats the winner).^{[citation needed]}