Although it's natural to compare Barack Obama's map against that of the losing Democratic efforts in 2000 and 2004, perhaps the more interesting comparison is with 1992, as Bill Clinton won both the popular vote and the Electoral College by similar margins to Obama:
The Democrats seem to be on the verge of quarantining the Republicans to a few, relatively electorally dry areas. As compared with 1992, there has been a net swing of at least 19 points to the Republicans in seven states: Kentucky, Tennessee, Oklahoma, Louisiana, West Virginia, Wyoming and Arkansas. All of these states but Wyoming form a contiguous region, which we refer to as the "Highlands" region but which is more commonly called the Inland South.
As compared with 1992, this represents a significant loss for Democrats, as Bill Clinton carried each of Kentucky, Tennessee, West Virginia, Louisiana and Arkansas in 1992. As compared with 2000 or 2004, however, the loss of these states is less electorally relevant to the Democrats. Al Gore was not able to carry any of these states, including his home state of Tennessee, nor was John Kerry. If you're going to have to sacrifice a particular region of the country, this is not a bad one to sacrifice. The only state that may sting a little is Missouri, which shares much in common with this region and is quickly losing its bellwether status.
What's more, the Democrats have not had to sacrifice the entirety of the South. As compared with 1992, they performed better in North Carolina, South Carolina and Florida, and much better in Virginia. The three Southern states that Barack Obama carried but Bill Clinton didn't -- North Carolina, Virginia and Florida -- account for 55 electoral votes, nearly canceling out the 65 electoral votes from the seven Southern states (Georgia, Missouri, Louisiana, Tennessee, Kentucky, Arkansas and West Virgina) that Bill Clinton carried but Barack Obama didn't.
Elsewhere, the Democrats have now put the Northeast completely out of reach. Although some of these gains are superfluous, at least four former swing states (New Hampshire, New Jersey, Delaware and Maine) no longer seem to fit that description. The Democrats have also gained ground in essentially all states in the industrial Midwest except Minnesota, but including Michigan, Indiana, Wisconsin, Illinois and Iowa, (and by smaller margins Ohio and Pennsylvania).
West of the Mississippi, there is something of a parallel pattern to the South. Democrats have fallen further behind in the Mormon belt -- Wyoming, Utah and Idaho, but have gained ground in Colorado, New Mexico, Nevada, Oregon and Washington. Arizona may be more fruitful with John McCain off the ballot in 2012. Only in California do their gains seem somewhat superfluous, but there is some utility to them in having a large enough cushion that they do not need to defend the state.
Essentially, by sacrificing 50 or so Electoral Votes from the inland South, the Democrats have taken about 60 votes from former swing states and turned them into Lean Democratic states, and another 44 or so from former lean Republican states and turned them into swing states. This is a good trade-off.
Former swing states which are now lean Republican (45):
Former lean Democratic states which are now lean Republican (5):
West Virginia (5)
Former swing states with are now lean Democrat (60):
New Jersey (15)
New Mexico (5)
New Hampshire (4)
Former lean Republican states which are now swing states (53 EV):
North Carolina (15)
Former lean Democratic states which are now swing states (0 EV):