Figure 8. The different temporal communities observed in the senator voting similarity network.

(a) The dominant temporal communities can be identified with the modern day Republican (in red) and Democratic (in blue) parties. (b) and (c) Minor communities are also found, which consist of republicans and democrats who often differ in their voting behavior from the majority membership of their party, as well as independents. (d) The number of atypical senators defined as those whose temporal communities are different from their declared party affiliations. Our results indicate that the number of such senators has been decreasing with time, perhaps indicating increasing polarization.