Do left-wing critics of immigration, such as Labor MP Kelvin Thompson, speak for a significant constituency?Joshua Gans seems to think so and argues that debates about immigration ‘cut across usual left-right divides’, evidence for this could include right-wing libertarians who support high immigration. It is true that 1970s doomsday fears of overpopulation were an early manifestation of Australian environmentalism, one that contemporary Greens are probably rather embarrassed about (today their cause is represented by Sustainable Popualtion Australia which includes some former Australian Democrats such as John Coulter). We could also consider projects such as CSIRO’s Future Dilemmas. However the 2007 Australian Election Survey (available from ASSDA) suggests that views about immigration are clearly polarised on a left-right basis. When asked if current numbers of migrants into Australia had not gone far enough or not gone nearly far enough only 6.5% of Liberal voters agreed, Nationals were even less at 4.1% but 18.2% of Labor voters agreed and 29.8% of Green voters. Among Green voters humanitarian support for high immigration swamps environmental concerns. The pattern is even clearer if we examine voters by their self-identification as left or right as shown the graph above.