For the Northeast, the last realignment election could either argue to be 1960, or 1992. I would argue 1960, as the Northeast was won by Republicans only 4 times since, 72, 80, 84, and 88.
For the Midwest, I would say the last realignment election would be 1992.
For the South, I would argue The last realignment election would be 1980, As Republicans have won a majority of states in this segment each election since. (12,14,13,8,8,14,14,11,12)
For the West, I would argue 1992 would be the last realignment election. This has been a tossup region ever since then.
