<Li> The system may promote votes against more so than votes for . In the UK, entire campaigns have been organised with the aim of voting against the Conservative party by voting either Labour or Liberal Democrat . For example, in a constituency held by the Conservatives, with the Liberal Democrats as the second - place party and the Labour Party in third, Labour supporters might be urged to vote for the Liberal Democrat candidate (who has a smaller majority to close and more support in the constituency) than their own candidate on the basis that Labour supporters would prefer an MP from a competing left / liberal party than a Conservative one . Similarly in Labour / Lib Dem marginals where the Conservatives are third, Conservative voters may be encouraged or tempted to vote Lib Dem to keep defeat Labour . </Li> <Li> If enough voters use this tactic, the first - past - the - post system becomes, effectively, runoff voting--a completely different system--where the first round is held in the court of public opinion; a good example of this is the Winchester by - election, 1997 . </Li> <P> Proponents of other single - winner electoral systems argue that their proposals would reduce the need for tactical voting and reduce the spoiler effect . Examples include the commonly used two - round system of runoffs and instant runoff voting, along with less tested systems such as approval voting, score voting and Condorcet methods . </P> <Table> <Tr> <Td> </Td> <Td> This section does not cite any sources . Please help improve this section by adding citations to reliable sources . Unsourced material may be challenged and removed . (September 2015) (Learn how and when to remove this template message) </Td> </Tr> </Table>

In the us plurality and majority systems tend to