All good scary stories have an element of truth. Yes, Democratic turnout is comparatively lower than Republicans in midterm elections compared to presidential elections. Yes, Democrats are disadvantaged by this. Yes, Republicans are trying to restrict voting in the names of vote fraud and election uniformity.
To demonstrate, I calculate the share of the 2006 and 2010 electorates on their age, race, and education profiles as reported by the Census Bureau's Current Population Survey, Voting and Registration Supplement.
The demographic profile of the 2006 and 2010 electorates are not all that much different, essentially bumping around within statistical error. If you squint, the 2010 electorate was slightly older than the 2006 electorate, but at the same time there were more persons of color. The latter is a trend that will likely persist in 2014 as the nation continues to become more diverse.
The 2006 Democratic victory thus shows that while lower Democratic turnout in a midterm election is a hurdle, it is one that can be overcome. Planned attempts by Democratic organizations to build a presidential-style field operation to mobilize those who typically drop out in a midterm election can be important to tilting the playing field. However, it is perhaps at least, if not more, important for Democrats to persuade swing voters to support their candidates.