Parapolitics and roll-call voting in colombia: a bayesian euclidean and spherical spatial analysis

This study presents a Bayesian spatial voting analysis of the Colombian Senate during the 2006-2010 legislative period, leveraging a newly constructed roll-call dataset comprising 147 senators and 136 plenary votes.We estimate legislators' ideal points, understood as latent positions in an underlying policy space that summarize each senator's overall political preferences, under two alternative geometric frameworks: a traditional Euclidean model and a circular model that embeds preferences on the unit circle.Both models are implemented using Markov Chain Monte Carlo methods, with the circular specification capturing geodesic distances and von Mises-distributed latent traits.The results reveal a latent structure in voting behavior best characterized not by a conventional left-right ideological continuum but by an opposition-non-opposition alignment.We then study the "parapolitics" scandal, a major episode in which numerous Colombian politicians were investigated and prosecuted for alleged ties to paramilitary groups.Using Bayesian logistic regression, we investigate the association between senators' ideal points and their involvement in this scandal.Findings indicate a significant and robust relationship between political alignment and parapolitics implication, suggesting that extralegal influence was systematically related to senators' legislative behavior during this period.