Clearly, 2010 was a contentious year in politics. It makes sense that articles about partisanship played such a prominent role in political discussions; party members voted against their party line infrequently, and the parties themselves took dramatically more opposing stances than in previous years. While a 20-year trend was not entirely clear in either intra-party partisanship or cross-party agreement, partisanship still clearly has changed towards more extremity recently, raising troubling questions for our current political balance.
I've learned quite a lot from this project. My biggest challenges were conceptual; I originally began by examining partisanship only through the so-called "Partisanship Ratio" for individual votes within a party, but soon saw trends in party agreement that reflected a macro-scale effect of partisanship that I was missing, leading to my second hypothesis. I acknowledge that my two-tiered frame for analyzing inter-party politics is far from perfect, but I do believe it serves a function in distinguishing between partisanship within parties and agreements between parties.
More than anything else, I wish I had more data! I think trends within a smaller time range might be more easily traced than those over such large time frames, and more data points would add to their legitimacy. A comparative study of partisanship in differing economic (recession vs. boom) and social (war vs. peace, etc.) conditions could also provide interesting insights into how various political factors interact to shape the choices Congressmen make.