Do realignments exist?

[pbrower2a]

They do happen, even if it takes a few election cycles for them to become significant.

Case in point:

Carter 1976,  Gore 2000, Kerry 2004  104
Ford 1976, Gore 2000, Kerry  2004  138
Carter 1976 George W. Bush 2000/2004  141
Ford 1976 Gore 2000 Bush 2004 11
Ford 1976 George W. Bush 2000 Kerry 2004  4
Ford 1976 George W. Bush 2000/2004 137

When in a close election the bare winner gets roughly half of his electoral votes from states that went for the nominee of his Party 24 or 28 years earlier and about half his electoral votes from states that went for the nominee of the other Party 24 or 28 years earlier, then one has a realignment.

[pbrower2a]

[
Now let's see how things go when we have Barack Obama in 2012:

They do happen, even if it takes a few election cycles for them to become significant.

Case in point:

Carter 1976,  Gore 2000, Kerry 2004 Obama 2012 104
Ford 1976, Gore 2000, Kerry  2004  Obama 2012 138
Carter 1976 George W. Bush 2000/2004  Romney 2012 141
Carter 1976 George W. Bush 2000/2004  Obama 2012  29
Ford 1976 Gore 2000 Bush 2004  Obama 2012 11
Ford 1976 George W. Bush 2000 Kerry 2004  Obama 2012 4
Ford 1976 George W. Bush 2000/2004 Romney 2012 46
Ford 1976 George W. Bush 2000/2004 Obama 2012 61

2012 was not really a close election in electoral votes, but it easily could have been -- had Romney won Florida, which he was about to until the last week of the electoral contest. Fully three fourths of the electoral votes that Romney won in 2012 were from states that Jimmy Carter had won in 1976.