Brian Beutler on the Democrats' bad week. One thing that should be added here is that a lot of Democratic members of congress are unprepared for the new realities of American legislative life because, for the members, those realities basically suck. The days of weak party discipline and relatively low levels of partisan/ideological alignment meant that life as a member of the US House of Representatives was much more pleasant than was life as a member of parliament in Canada or France or what have you. Consequently, a lot of members would like to believe that with the Big Bad DeLay gone they can somehow resuscitate the grand old days of cross-cutting coalitions and free-agent members rather than the dreary business of party discipline and endless legislative trench warfare.
In the real world, though, the causes of partisan polarization are structural and DeLay and Gingrich were just symptoms, or perhaps smart people who understood how to take advantage of the new realities.