To see how the base of the Republican Party has changed over the years, compare two presidential elections, 1944 and 1988. In both, the winning candidate was the nominee of the party that had long held the White House—for three terms by 1944 and for two terms by 1988. The winning candidate in both cases found his strongest regional support in the South; his second-strongest region was the West. Both times, the winning candidate narrowly carried all but one of the large Eastern and Midwestern states—New York, Pennsylvania, Ohio, Michigan, Illinois.
One thing was different. The winner in 1944 was a Democrat, Franklin Roosevelt. The winner in 1988 was a Republican, George H.W. Bush.
There have been further changes in the Republican Party vote since 1988. George H.W. Bush won by large margins in affluent suburban counties. To take one example, Mr. Bush won 61% of the vote in the four suburban counties outside Philadelphia—Bucks, Chester, Delaware and Montgomery—and carried Pennsylvania. More recently, affluent suburbs outside the South—showing a distaste for cultural conservatism and for the increasingly Southern accent of the Republican Party—have trended Democratic. In 2008, Barack Obama won 57% in these four counties outside Philadelphia, and he carried Pennsylvania.
By contrast, the senior Bush got whipped in West Virginia, one of only 10 states he lost in 1988. He also trailed in the steel and coal country from western Pennsylvania and southeastern Ohio running down to eastern Kentucky and southwest Virginia. But in 2008, voters there turned up their noses at Barack Obama. He lost not only West Virginia but also Kentucky, Tennessee and Arkansas, all of which were carried twice by his fellow Democrat Bill Clinton.