Have you been thinking about the midterms lately? If you said yes, then you're like 42 percent of Republicans -- and just 27 percent of Democrats.

Those figures come from a new Gallup poll this week that marks the latest sign that Republicans are more engaged than Democrats with the midterm campaigns. Recent history suggests that will also be the case just before Election Day. The big unknown is how wide the gap between the two parties will be.

As the public has begun slowly tuning in to the midterms more this year, the disparity between Republican and Democratic interest has grown. In April, 37 percent of Republicans had given the midterms "some" or "quite a lot" of thought, a larger share than the 24 percent of Democrats who said the same thing. Now, the gap is 42 percent/27 percent in favor of Republicans.

A look at the three most recent midterm elections suggests two things: First, levels of Republican and Democratic engagement are almost certainly going to change between now and Nov. 4.  Second, despite the expected fluctuations, Republicans are expected to hold their engagement advantage.

The following chart from Gallup tells the story. In 2010, a GOP wave year, the Republican advantage shrunk between the summer and the fall. In 2006, a Democratic wave year, it fluctuated dramatically. But even then, Republicans held a modest four-point engagement advantage in November. In 2002, when Republicans gained seats, GOP interest -- relative to Democrats -- shot up in the fall.

So what does this all mean for 2014? Overall, good news for Republicans.

Republican engagement relative to Democratic engagement at this point in the election cycle is closer to what it was in 2010 -- a banner year for Republicans -- than 2006. Their advantage would have to shrink significantly between now and November for it to disappear altogether.

The stronger interest Republicans have shown in recent midterms is why Democrats are looking for something -- anything -- to get their core voters jazzed about going to the polls. Their pitch to elevate the Koch brothers as bogeymen is a play to their base. So is talking about social issues and parochial concerns.

The burden is on Democrats to shrink the enthusiasm gap significantly before November. If they don't cut it down, it's going to be a long winter.