What do Salvador Allende, the British Labour left of the early 1980s, the 1989-92 Tasmanian labor government and contemporary left-wing advocates of proportional representation have in common? All overestimated the power of narrow majorities. In a recent speech Geoff Gallop argues that proponents of proportional representation such as the Australian Greens are seeking ‘rule by the percentages’. His argument seems to be that PR by further weakening major parties would mean that governments would have even less prospect of promoting necessary change. I like the phrase ‘rule by the percentages’ but to me it calls up a rather different problem. Many on the left seem to believe that because PR would make a nominally ‘left’ parliamentary majority more likely it would encourage progressive governance. However in the absence of wider consensus just holding power is not enough for the left to implement radical change. Salvador Allende was elected President of Chile in 1970 on 37% of the vote over a conservative and centrist opponents. Perhaps in a run-off system Allende would have defeated the candidate of the right but 37% was a very limited mandate for the Chilean road to socialism to socialism and the Chilean Communists were aware of this to their credit). The British Labour left of the early 1980s hoped for the election of a radical Labour government as a result of a popular reaction against Thatcherism. Labor’s two previous election victories in 1974 were on support of 43% and 37%. It was unrealistic for the left to imagine that a radical Labour government elected in the early 1980s on a vote of probably no more than 40% could have successfully implemented its program. In 1989 Tasmanian Labor polled only 34.7% compared to 46.9% for the Liberals but Labor formed a government with Green support. At the 1992 election Labor received only 28.9% and the Liberals 54.1%. Did voters consider that Labor’s government was illegitimate? PR might assist parties of the left to cobble together electoral majorities but this will not reflect a natural left-wing majority in the electorate.