Steven Hill on fusion voting, which is having something of a moment in the sun as reformers push to eliminate fusion bans.
It does that by allowing a candidate to appear on the ballot under multiple political party labels simultaneously – for example, Democrat and Green and Labor – and the voter has the option of voting for that candidate as the standard bearer for any (but only one) of those political parties. The votes for the candidates are tallied separately by party, and then added together to produce the final outcome. This also allows the smaller political party to register its public support without taking a chance of running its own candidate and (in the example above) splitting the center-left vote among too many candidates, thereby allowing the candidate they all like the least (their “greater evil”) to win. This dynamic would work exactly the same among conservative candidates and voters from the center-right to further-out right.
In short, fusion – also known as cross-ballot endorsements – gives the smaller party more brand recognition along with its own ballot line. Minor parties often have difficulties fielding a candidate in every race, so fusion also allows that minor party to try to use its ballot line to influence even those races in which it has not been able to recruit its own candidate by dangling its endorsement in front of a major party candidate (though that feature has led to some partisan shenanigans and horse trading – more on that below). If the race is close, the minor party endorsement might play the role of kingmaker.