Do the dynamics of behavior in a legislature indicate political stability or, on the contrary, portend instability, even armed conflict? Are the members of a legislature in fixed ideological positions, necessitating that political chance occur as a result of the selection of new representatives through the political process. Or do legislators adapt to the changing demands of their constituents? How do new legislatures, like the United States Congress in 1789, the United Nations General Assembly in 1946, and the European Parliament in 1979 organize themselves politically? How is a legislature affected by a massive change in membership, as has occurred with the recent enlargement of the EU? How does behavior of new legislators develop in an ongoing legislature? How do legislatures respond to increasing political tension on a variety of issues ranging from slavery to abortion? This essay focuses on the use of animation in addressing these and other questions.

A picture is worth 1000 words. A moving picture can be worth 1000 time series regressions. This paper is particularly concerned with moving pictures that are animations of time-series estimates of the dynamics of behavior in voting bodies. The empirical focus is the European Parliament, the United States Congress, and the United Nations General Assembly. Animations of these legislatures can be viewed at voteworld.berkeley.edu.