Bayesian modeling of the political preferences of the Colombian Senate 2006-2010: electoral behavior and parapolitics

In this paper, a Bayesian spatial voting model is applied for the first time to characterize the legislative behavior of the Senate of the Republic of Colombia for the period 2006-2010. The analysis is carried out based on the plenary nominal votes of the Senate. The estimation of the model is done using Markov Monte Carlo chain algorithms. The estimated ideal points provide empirical evidence supporting a latent non-ideological feature (opposition--non-opposition) underlying senators' voting. Additionally, the relationship between the parapolitics scandal and the legislative behavior of senators is analyzed through a logistic model, both Bayesian and frequentist. The results indicate a significant relationship between being or having been involved with the parapolitics scandal and the legislative behavior of the senators from the period 2006-2010.