There's some back and forth today about what this all means for the "Emerging Democratic Majority" that so many were excitedly anticipating a few years back.  James Joyner sums up a recent paper on realignment elections:

Some elections are realigning and others are not: The attempt to dichotomize elections between critical and non-critical ones is flawed. Rather than thinking about partisan change in terms of peaks followed by long periods of stasis, we should think about change as a mixture of large, medium, and small effects. In other words, a gradual change model is better than a punctuated equilibrium model.
  • Periodicity: The "30-year pattern" seems very dubious. If the critical/non-critical dichotomy is invalid, then so is the periodicity hypothesis.
  • Tension and flash points model: The realignment model of a gradual build-up of tension that then triggers a major shift at a critical election is flawed. The realignment model looks too far back in history to explain shifts in party ID, which can often be better explained by proximate events.
  • Concern and turnout are higher at realigning elections: Seems modestly accurate for 1860 and 1896, but not 1932.
  • The emergence of a new cleavage causes a realignment: Not necessarily; events may do a better job of explaining changes in voter attachments.
  • Ideological polarization is associated with realignment: No, the realigning elections (1860, 1896, 1932) don't all seem to be accompanied by ideological polarization, particularly 1932.
  • Realigning elections are national; non-realigning ones are local: Empirically, this doesn't seem to be so clear.
  • Realignment leads to major policy changes: Seems to be true for 1860s and 1930s, but not the 1890s.
  • Realignments are about redistribution: Seems to be true of 1860s and 1930s, but not the 1890s.
  • Major contributions to the political system are made about once a generation: No, political parties respond to changing preferences on an on-going basis.
  • The 1896 election ushered in an era of business dominance: Probably not. Business was already doing fine before 1896 and appears not to have needed insulation.
  • To me, realignment elections involve incredibly traumatic events:  the civil war, the Panic of 1893, the Great Depression (it's not clear that 1860 would have ushered in such GOP dominance if the civil war hadn't followed it).  We're talking about events that sear themselves into voters' minds so thoroughly that people who came of age during the trauma can never again bring themselves to pull the lever for the other party.  You get generational dominance.

    What we're going through now is just not that bad.  Not to minimize it--but if you know anything about the Great Depression, you know how modest modern-day suffering is in comparison.  In my previous post, I urged a WPA-style jobs program, and I would actually support such, but it could never have the power that the WPA and its brethren did, because the persistent poverty of the era simply doesn't exist now.  I'm talking about 25% unemployment, but also about the much lower living standards that constituted the "average American" life before World War II.  People were closer to the line of malnutrition, starvation, freezing to death--and when the crisis hit, it was easier for many, many to fall below it, particularly given the level of unemployment.

    This is as it should be--and why I'm in favor of more generous unemployment benefits.  But the very safety of the safety net, and the lack of a horrible civil war killing tens of thousands of young men, means that no party is so thoroughly associated with utter destruction as to be barred from office for a decade or more.

    Democrats thought that had changed in 2008.  But I don't think it has.  For which we should all be very grateful--no matter how fond we are of Democrats.