Aldrich.
Partisanship has decreased in America. Party politics are not what they once were. Political parties were much stronger before the mid-1960's, a critical point in the political timeline of the U.S. Sisnce then, there has been stable periods, with the 1990's showing signs of another critical period.

Where are we now, and what are the indicators of political stability in America in 2006?

I don't want to cop out of this answer, but I really think making this decision (if we are in a stable period or critical one) is something that can only really be done further on. I know the political composition of the nation does not FEEL stable. This may be a very Steven Colbert-type discription, but it seems accurate. Political parties don't feel weak right now, and our nation is and has been reeling for a number reasons that indicate the opposite of stablity. Maybe it was the heated elections, maybe it's sexy political issues like gay marriage that has been rattling my cage, or maybe it's just because I tend to be more sensitive to the political world than most, but the point is that I feel like the nation is not politically stable.

But does a very debateable "culture war" mean political parties or their institutional form are less stable? I don't know if it does.

What is really going on with the political makeup of the nation right now? Why is it so easy to talk about red and blue, the "East Coast liberal elite" or "Southern conservatives?" What was the electorate's motivation in 2004 and 2006, and how do parties make a difference?

To me, Aldrich defined the critical period of the 1960's as being a time when partisanship and the institutions of parties itself were changing - not that regions realigned themselves with parties and voted, but how groups of people where defining their own partisanship and the nature of parties. So parties are stable now; stable in their instablity. There is no Reform party taking 20% of the national vote and no major demographics shooting up.

Despite the spark the Democrats have right now, I tend to think the national tide will not result in a critical period in American politics (as far as Aldrich will be concerned looking back at the data in years to come). We are in a stable period as far as partisanship definations go even thought the congress has switched.

Different groups do have the potential to realize they are leaning the wrong way, which I find very intersting. Like religious groups getting into the debate about the environment or the 10% of the nation that is gay realizing they want to have health benefits or sportsmen who have less public land to hunt on. Even more likely, christian conservatives banning together led by a handful of ministers, that realize they have the power to break away from the Republican economic agenda. That would be something. I don't see it happening, but if any group were to mobilize it would be the christian conservatives pulling from situations hurting them economically.

2006: not critical but only stable in the consistent instability.