In their seminal 1980 study on the question, using data from 1972, political scientists Raymond Wolfinger and Steven Rosenstone argued that “voters are virtually a carbon copy of the citizen population.” In 1999, Wolfinger and his colleague Benjamin Highton again came to the same conclusion: “Outcomes would not change if everyone voted.” Their argument rested upon the fact that polling data did not show large differences in opinions on most issues between those who voted and those who did not.
However, a growing literature both within the United States and internationally suggests that, in fact, policy would change rather dramatically if everyone voted.
Does this mean that Galbraith was right all along? Not exactly. The reason for the recent shift in the findings is not that the early studies were wrong, but that the preferences of voters and nonvoters are becoming increasingly divergent. In a paper published in 2007 and later expanded into a 2013 book, Who Votes Now,political scientists Jan Leighley and Jonathan Nagler found that wide gaps between voters and nonvoters have opened up when it comes to class-based issues. They argued further that the seeds of these differences were apparent in earlier data, but Wolfinger and Rosenstone overlooked the gaps by focusing on broad ideological labels (liberal or conservative) rather than specific policies. Voters, Leighley and Nagler found, are more economically conservative; whereas non-voters favor more robust unions and more government spending on things like health insurance and public schools.