We here study the behavior of political party members aiming at identifying
how ideological communities are created and evolve over time in diverse
(fragmented and non-fragmented) party systems. Using public voting data of both
Brazil and the US, we propose a methodology to identify and characterize
ideological communities, their member polarization, and how such communities
evolve over time, covering a 15-year period. Our results reveal very distinct
patterns across the two case studies, in terms of both structural and dynamic
properties