Voting Systems
Supplementary Vote
What is the Supplementary Vote?
With the supplementary vote, there are two columns on the ballot paper – one for the first choice and one for the second choice. Votes are marked by placing one 'X' in each column, although voters are not required to make a second choice if they do not wish to.
All the first-preference are tallied, and if a candidate has a majority, they are elected. If no candidate receives a majority, the top two candidates are retained, and the rest eliminated. The second-preference votes of the eliminated candidates are then counted, and any for either of the top two candidates are added to their first-round totals. Whichever candidate has the most votes after these second-preferences have been allocated is declared the winner.
Real-world application of SV
All directly elected English mayors, most notably the Mayor of London.
Arguments used in support of SV
- To some extent, SV encourages conciliatory campaigning, as gaining second-preference votes is important.
- It is a relatively simple system to understand.
Arguments used against SV
- SV suffers from all of the disadvantages of AV.
- SV does not eliminate the likelihood of tactical voting.
- Unlike AV, SV does not ensure that the winning candidate has the support of at least 50% of the electorate.
- SV strongly promotes voting for only candidates from the main three parties.
- If there are more than two strong candidates, voters must guess which two will make the final round, and if they guess incorrectly, their second-preference vote will be wasted.