“The ad wars” is a series Wonkblog will be running semi-regularly until the election, in which George Washington University political scientist (and Monkey Cage founder) John Sides shows you what’s really happening on the airwaves.

Last week, for the first time this fall, Republican advertising in the presidential election essentially matched Democratic advertising.  In the period from Oct. 22-27, the Democrats aired about 38,700 ads — this is Obama plus any Democratic super-PACs — while Romney and his allies aired about 38,200 ads.  

Two other facts about this increase in Republican ads.  First, it is being driven by super-PACs, not by the Romney campaign — as this graph demonstrates:

Second, the increase is particularly striking in the state of Ohio, as this graph demonstrates (click to enlarge):

This suggests that, despite the additional spending that the Romney campaign is now devoting to states like Pennsylvania and Michigan — not yet captured in the data through Oct. 27 — the real money is where it’s always been: in Ohio.  If we can infer strategy from spending, the GOP sees Ohio as the linchpin of victory.

And they are now outspending Obama there as of this past week.  Here is a graph that demonstrates each side’s targeting strategy:  

The Republicans’ advantage in Ohio is evident here.  The GOP is also running more ads than Democrats in Michigan, Iowa, Missouri and New Hampshire.  Perhaps most interesting is the continuing strategy of Obama to spend heavily in Virginia and Florida, a strategy that suggests he thinks both are in play, even though Florida in particular is still leaning toward Romney.

As I wrote at The Monkey Cage, these late advertisements are perhaps the most persuasive of the campaign.  But will either campaign muster enough of an advantage on the airwaves in these final days to move voters?

As has been true, the Republican advantage in spending does not translate into an advantage in the number of ads, due to the differential rates they are paying.  Some reporting also suggests that Obama has been better able to get his ads in highly watched programs.  But given the rough parity in the volume of ads, and the fact that GOP spending is on the rise, I am doubtful that either party will muster a significant advantage heading into Election Day.