It all makes sense now.
According to Edward McClelland writing for Slate, air conditioning has made this country into what it is today, whether you like what it has become today or you don’t. If it hadn’t been for air conditioning, Florida would still have a million people and six electoral votes.
But the central McClelland’s central question, “Does air conditioning make people vote Republican?” goes unanswered. Yes, states like Arizona and Florida exploded in population, as did Republican fortress Texas. But where did these people come from?
In line with the grand “suburbanization” of America, most of them probably came from northern and midwestern cities where their moderate to conservative Republican votes were often drowned out by strong urban Democratic party machines, rendering them irrelevant in the several states in which they lived.
Air conditioning allowed all of these city escapees to concentrate in large numbers in a the south and southwest, banding together and creating areas with large amounts of electoral votes. (Yes, Idaho and Montana are usually solidly Republican but with all of 4 and 3 electoral votes respectively, so what?)
So while air conditioning might not make people vote Republican, it definitely seems to have made a lot states go Republican.
I went to 270towin.com and had a little fun with their historical maps of past presidential contests. Though you can’t see it because of the size of this map, Arizona and New Mexico each have 3 electoral votes, Florida has 7, and Texas 23. That year, they all happened to vote Democratic, sending FDR to his third term.
Electoral map from the 1940 presidential election
Sixty years later, those numbers (and the electoral landscape) had changed radically:
Electoral map from the 2000 presidential election
By 2000, Arizona had gotten 5 more electoral votes, New Mexico 2 more, Texas 9 more and Florida, a whopping 18 more electoral votes. Meanwhile, Pennsylvania lost 13, Illinois 7 and Massachusetts 5. Texas, Arizona and Florida (and New Mexico in 2004) all shifted from Democratic to Republican with 34 more electoral votes under their control.
Of course, this doesn’t explain why states that didn’t “benefit” by the spread of A/C (Ohio, I’m looking at you) switched over to the red column. But, as a swing state, Ohio could have gone either way in any of the last several elections. The point is, the solid south (and southwest) have put themselves in the Republican category, it would seem, with a lot of a/c carrying folks moving in.