There has been much discussion in the media as to whether the 2008 election represents an electoral realignment. The short answer is: it is too soon to know. Perhaps the best way to look at the issue is to recognize that there were some dynamics within the 2008 election results, especially when considered in tandem with the 2006 midterm election results, which indicate the possibility of an electoral realignment. Only after the 2010-2012 elections are in the books will we know whether a realignment has actually occurred.
My argument on this question would be that certain electoral shifts have clearly occurred over the past two national election cycles. These have resulted in dramatic Democratic victories, with Democrats gaining over 50 House seats, at least 13 Senate seats (depending upon the outcome of the Minnesota recount) and taking the White House with the largest portion of the vote for either party since 1988, and the largest Democratic majority since 1964. There have been some rather dramatic demographic and geographic electoral shifts since 2004. These shifts have been almost uniformly fortuitous for Democrats, and ominous for Republicans.
Republican Party identifiers constitute a shrinking, according to party identification numbers from the election-day exit polls, percentage of the electorate. Democrats have virtually wiped out the Republican Party as a viable entity throughout the Northeast, and Republicans are struggling to sustain viability in much of the Upper Midwest and Great Lakes Midwest region. Democrats in these regions have made substantial inroads into suburbia, winning the suburban vote surrounding many of the largest cities in both regions.
Democrats also now clearly dominate the Pacific Coast and have made inroads in the Mountain West, especially the Southwest states with substantial Latino populations, including Colorado, New Mexico, Nevada and Arizona. Democrats have also performed much better in certain Southern "growth" states along the Atlantic Seaboard, particularly Virginia and North Carolina, and to a lesser extent Florida. Virginia and North Carolina are states which have experienced population growth from migrants, largely well-educated, who tend to be more liberal and more Democratic in affiliation than the native born inhabitants of the two states. The trend toward Democrats in Virginia and North Carolina is counter-balanced by the Democrats' worsening performance in the culturally conservative Interior and Border South, a nine-state region stretching from West Virginia in the east to Oklahoma in the West. This section of the nation has become even more Republican in recent elections, and now represents the core of Republican support. The danger for Republicans is that as their geographic base shrinks, the party is pulled in a more conservative direction, lessening its appeal to centrist elements within the electorate.
The results of 2006 and 2008, by granting United Government under Democratic control, have provided Democrats with an opportunity to cement their electoral gains through effective governance. There is an opportunity to shift public policy. If those policy shifts which are enacted into law are retrospectively viewed by the electorate as having been effective, then the electoral gains of 2006-2008 are likely to be further reinforced, resulting in a recognizable and enduring realignment. If the policy shifts are largely viewed as ineffective in addressing the nation's perceived problems and major national issues, the opportunity for achieving realignment is likely to fade.
Basically we need to recognize that while there clearly have been some notable shifts in electoral coalitions of the two parties in recent years, we are not yet in a position to validate an enduring realignment. These shifts have created the opportunity for an enduring realignment. Effective, responsive governmental policy shifts would serve to further enhance the possibility of an enduring realignment.