As we move into the 1960 election (see previous post on the 1948 election), one of our 10 States of American Politics clearly comes into view. The Northeast Corridor had been part of the Republican base since the Civil War, and Republican Tom Dewey carried it by some 25,000 votes over Harry Truman in 1948, but it went strongly for Democrat John F. Kennedy over Richard Nixon 12 years later. Kennedy got 54.2 percent of the vote here, running almost exactly 8 points ahead of Truman. Nationally, Kennedy got 49.7 percent of the vote, or just one-tenth of a point more than Truman. Most importantly in terms of the Electoral College, Kennedy won six Northeastern states that Dewey had carried in 1948: Connecticut, Delaware, Maryland, New Jersey, New York, and Pennsylvania. Without them, he would have lost badly to Nixon. The map of the Northeast Corridor shows that Kennedy won this region -- and the election -- by greatly increasing the Democratic share of the votes in the suburbs around New York, Philadelphia, Baltimore, and Washington. And ever since, these counties have been increasingly important for Democratic presidential nominees.
Here's the national map of the vote swing between 1948 and 1960. Note that Kennedy greatly increased the Democratic vote in parts of the Deep South, but that was because Dixiecrat Strom Thurmond had pushed down the Democratic vote so much in 1948; the Democrats' recovery here would be short-lived. More important, in the long run, would be the drop in the Democratic vote in fast-growing areas of the West.
Here's the national picture of Kennedy's share of the vote by county.
And here's the raw vote margin. Note the patches of blue in Illinois, Michigan, Minnesota, Missouri, South Carolina, and Texas -- all states that Kennedy narrowly carried.