This is particularly the case in midterm elections. Turnout nationally is well under 50 percent of the voting age population, meaning that each individual vote counts more toward the electoral outcome than in higher turnout races. That leads to intense turnout efforts by campaigns, parties and interest groups.
Voting is not a natural act. Most people have goals more important to them than trudging to the voting booth. In their excellent book Mobilization, Participation and Democracy in America, political scientists Steven J. Rosenstone and John Mark Hansen focus on how campaigns, parties, and interest groups serve to lower the costs of participation in order to get "their" voters to the polls. As they put it: "Thus, the strategic calculations of political leaders determine a lot about who participates. Intent on creating the greatest effect with the least effort, politicians, parties, interest groups, and activists mobilize people who are known to them, who are well placed in social networks, whose actions are effective, and who are likely to act."
Turnout is stimulated by lowering time and information costs for citizens targeted by these organizations. TV and radio ads, direct mail, emails, tweets, and phone calls all are aimed at lowering those costs so that turnout becomes easier and, collectively, higher among the targeted group of voters.
This means effort disproportionately focuses on "the organized, the elite and the advantaged," according to Rosenstone and Hansen. That will particularly be the case in 2010's low turnout elections. It's as much a verdict on who best stimulates turnout by lowering participation costs as it is a decision about who wins.
So far in 2010, high levels of interest among GOP partisans mean that they perceive less cost to voting than do Democrats. That may make the targeted messages more effective and yield Republican success in the elections. We shall see.