This article explores under what institutional conditions senator-initiated bills pass. We explore how bill content and committee referral interact with presidential urgency motions, chamber leadership/seniority, and changes in lawmaking rules shape the probability of enactment. Using an original data set of 2993 Senate bills (1990–2022), we estimate logistic models and visualise predicted probabilities by bill content, committee referral, authorship resources, and institutional signals. Presidential urgency motions are the strongest correlates of passage; leadership positions and seniority increase success, whereas committee membership does not. Bills on symbolic or low-conflict topics pass at higher rates than national policy proposals; constitutional-committee referrals fare better than economic-committee referrals. Reforms in 2005 and 2010 expanded legislative entrepreneurship but reduced average success as bill volume surged. These results refine executive-dominance accounts: in Chile, a legislator’s initiative become law primarily when the presidency validates it and when leadership and experience align to push it forward.
Faúndez-Caicedo et al. (Tue,) studied this question.