We were hardly the first to call attention to this; it has become a relatively common refrain among Republicans, who suggest that the gap in turnout indicates a deeper gap in enthusiasm between the parties. This is perhaps better demonstrated by looking at the change in turnout for each party since its last contested nomination -- the Republicans in 2012 and the Democrats in 2008.
Turnout for the Republicans is way up. Turnout for the Democrats is way down.
But, then, we're comparing the historic election of 2008 for the Democrats with the exceptional election of 2016 for the Republicans. So this, too, seems like it might be an outlier.
But even that may be beside the point. The question is a simple one. Does this mean anything? Is it revelatory that the Republicans are beating the Democrats in turnout this year?
Unfortunately, we have very little data to look at. Since 1972, the first nomination process after the Democrats revised their nomination process, there have been only four years in which both parties had a contested nomination: 1988, 2000, 2008 and 2016.
In other words, we have a very small sample size. After all, we can't compare turnout in a year like 2012 with turnout this year, because the Democrats had very little incentive to actually get to the polls four years ago.
We also have a small sample size this year -- four contests, during which the Democratic field has been winnowed to two and the Republican field still has five. If you look at the early contests in each of the previous doubly contested years, you can see a pattern: The party without an obvious front-runner had higher turnout both in the first few contests and overall.
In 1988, George H.W. Bush was the obvious nominee for the Republicans, so the hard-fought Democratic contest had more turnout. In 2000, the Democrats also had a sitting vice president running, and the Republicans had higher turnout. In 2008, the Democrats had far more turnout overall because their nomination contest lasted longer -- as the obvious front-runner crumpled and the race dragged into June.
So what happened in those races? We can look at which party had more votes between the two of them in both the early voting states and throughout the contest and compare that with the final vote tally. In 1988, the Democrats had a higher turnout and lost. In 2000, the Republicans had a higher turnout -- and lost the popular vote, although not the presidency. In 2008, the Democrats won both.
In other words, it's a mixed bag. Three contests with a whole slew of different factors. In 2016, the Democrats have an obvious front-runner (Hillary Clinton) and a challenger who doesn't seem poised to repeat Barack Obama's upset. The Republicans, on the other hand, have one of the most interesting contested races in years.
So we don't know what the turnout advantage means, if anything. We should perhaps expect that a race with a front-runner like Clinton -- however tough her past few months -- would have lower turnout than the Republican side. Whether that means she'll win or lose is a totally different question.