In today’s New York Times John Harwood asks a question about tomorrow’s midterm primary elections, “Angry Voters, But How Many?”, which got our attention. He highlights the fact that not only was turnout for Barack Obama’s historic 2008 election underwhelming, but that it’s probably not going to get much better than that this time around.

In 2008, when Mr. Obama’s candidacy galvanized Democrats and intrigued the nation, nearly 4 in 10 Americans declined to vote. Even at peak interest, the American appetite for democratic rituals is hardly universal.

Without a presidential race to lead the ballot, the appetite is even weaker. The last time more than half of the eligible citizens voted in a midterm election was nearly three decades ago, in 1982, census figures show.

Students of modern political history point out that this is often a problem for Democrats. Their less-affluent constituency traditionally goes to the polls at lower rates.

“We usually do well when the turnout is low,” said John Morgan, a longtime Republican demographic specialist.

Comparing 2010 to one election with modest turnout in which his party captured both houses of Congress, Mr. Morgan observed, “This smells like 1946.”

Elections with low turnout can allow parties to tilt the outcome substantially through small shifts in the composition of those voting.

In the 1994 midterms, for example, overall turnout as a proportion of eligible citizens dropped slightly. But since Representative Newt Gingrich’s party was energized that year and President Bill Clinton’s was downcast, the result earned the moniker “Republican Revolution.”

“You can have a big-wave result,” Mr. Cook said, “without a big wave of voters.”

We’ll be monitoring tomorrow’s vote here. If you’re curious why we’re voting on Tuesday, the answer is here.

Photo of empty polling place via nonnormalizable on Flickr.