Has the 2008 election ushered in a new era of Democratic hegemony, akin to those enjoyed by the Democrats beginning in 1932 and the Republicans beginning in 1980? Two considerations suggest yes.
First, a Republican president is presiding over a deep economic crisis. The early-1930s and late-1970s crises scarred the party in power for a generation, and this one has the potential to do the same (John Judis makes a similar point).
Second, Barack Obama won big among young voters; according to exit polls, he got 66% of the votes of those age 18 to 29. This is important because while our party preference can in principle change at any time, we tend to stick with the party we identified with when we first became politically aware.
The following two charts show the role this played in the partisan shift that occurred around 1980. Both use data on party identification from the National Election Study (NES) and the General Social Survey (GSS). In the first chart, we see that among all American adults Democrats held a large advantage until the late 1970s, after which their edge diminished sharply. The second chart shows the trend for people who turned age 20 between 1978 and 1990. The formative political years for this cohort were ones of economic crisis under Democrats in the late 1970s followed by improvement (after 1982) under a Republican president and Senate in the 1980s. Among this group the party identification gap started small and had virtually disappeared by the mid-1980s. Through the 1980s, 1990s, and 2000s this cohort has slowly replaced an older generation of Americans who continued to identify with the Democrats. This process of cohort replacement is a key driver of the shrinking partisan gap among all adults that we see in the first chart.
Are we in the midst of an enduring shift in favor of the Democrats? We’ll only be able to tell in retrospect, of course, and I suspect much hinges on what the Obama administration can accomplish. But the groundwork appears to have been laid.
Lane Kenworthy 
How lasting and influential a party’s dominance is depends on the longer term success and value of what it actually does. FDR passed the New Deal, which was enormously beneficial. Once it was passed, and people saw how false the Republican claims against it were, and how much better it made people’s lives, and the country, the Republicans could never get rid of it. Their whole party was forced to move far to the left and accept it, or be voted out almost completely and become a minor party.
The enormous good from the New Deal allowed for 45 years of very strong Democratic dominance. By contrast, most of the policies of the conservative Republicans, by and large, did great harm over the medium and long run to the vast majority; they were discredited, and as a result, the Republicans’ dominance was only about 25 years and much less strong. And staying in power even that long was due largely to deception, distraction, appeals to racism, and big money from the rich and special interests.
The most important thing for Obama will be to pass Universal Healthcare. This would be like the New Deal and Medicare; once it was passed, and people saw how false the Republican claims against it were, and how much better it made people’s lives, and the country, the Republicans could never get rid of it. The whole party would be forced to move far to the left and accept it, or be heavily voted out and become a minor party.
Passing Universal Healthcare is crucial to lasting Democratic dominance and doing lasting good. I have a post on this at: http://richardhserlin.blogspot.com/2008/11/theres-nothing-more-important-for-obama.html.
With regard to people tending to stick with their first party, this is also true in marketing. I remember in my MBA days learning how hard companies try to get college students first out on their own to use their toothpaste and beer, knowing the likelihood that it would create loyalty that would last a lifetime.
One of the unfortunate weaknesses of academia is the reluctance of fields to learn from and work with each other; unfortunately the reward/penalty system fosters this, but it would be valuable for political science and sociology professors researching this to look at the marketing literature.
“Enduring shift” … didn’t we hear something similar to this not too many years ago from Carl Rove?
This isn’t the 1930s, whereby FDR could create a movement that dominated politics for a few generations. Things move too fast nowadays.
As a proud member of the Vast Right-Wing Conspiracy, I am plotting our comeback right now.
Thanks for posting this – its good to have actual statistics rather than just theory on this topic. I have long beleived that this might well a liberal’s 1980 – now I have some figures to back it up.
PS. I’m glad to have found your blog – I’m a poli sci student and have cited quite a few of your papers – my favorite one is your study of the relationship between the welfare state and aboslute poverty in developed countries.