Mecklenburg County has increasingly favored Democrats over the past several election cycles, and Larry Sabato of the University of Virginia recently pointed out that the county was one of many of the nation's largest to turn increasingly blue in recent history.
In 2012, 60.8 percent of voters in Mecklenburg went for Barack Obama compared to 38.3 percent for Mitt Romney. In 2000, George W. Bush carried Mecklenburg with 51 percent of the vote compared to Al Gore's 48.2 percent. George H.W. Bush won Mecklenburg over Michael Dukakis in 1988, 59.4 percent to 40.2 percent.
According to Sabato, the shift here and elsewhere reveals that success for Democrats now largely hinges on success in large cities:
Obama’s failures in rural Appalachia are worth noting, but even more so are Romney’s setbacks in the nation’s 50 most populous counties.
Romney won only six of the nation’s 50 largest counties (as measured by the Census Bureau). This was a significant drop-off from the last two winning Republican presidents, George W. Bush in 2004 — who won 16 of these 50 counties in 2004 — and George H.W. Bush in 1988 — who won a majority of these counties, 29-21, in his victory over Michael Dukakis.
Note that the Democratic margin in these counties generally increased over the three elections in question; granted, this is not necessarily an apples to apples comparison — we’re comparing a Democratic victory to two Republican victories, and the 50 biggest counties today were not the 50 biggest 12 or 24 years ago — but it’s still fair to say that just as Democratic strength is waning in rural America, it is growing in the country’s most densely populated counties.
Sabato notes that Appalachia has meanwhile gone the way of Republicans:
To see the change in the Democratic coalition over the years, first look at Appalachia. The mountainous region stretching from New York in the north all the way to Mississippi in the South was at one time a decent source of votes for Democratic presidential candidates: Southern Democrats Jimmy Carter (in 1976) and Bill Clinton (in 1992 and 1996) — the last two Democratic presidents before Obama — did reasonably well in the region in their victories: Carter won more than two-thirds of the 428 Appalachian counties in 1976, and Clinton won close to half (see chart below). In this election, the region was unkind to Obama; he won only 7% of Appalachian counties in his successful reelection bid last week. In fact, Obama lost every county in West Virginia, the only state wholly contained in Appalachia.