This paper seeks to investigate the behavior presented by the chamber of deputies, with regards to the bills which were presented by the executive power during the 2002–2006 legislative term. The author demonstrates that one of the most relevant reasons that the government of Ricardo Lagos was able to successfully pass the bills it favored, was the high unity of the governmental party and the heterogeneous action of the opposition bloc. Thus, through the use of Roll Call Vote analysis, this article assigns each of the parties and coalitions a percentage point relative to its degree of approval to the Executive's initiatives. This method indicates that the "Renovacion Nacional" was a pivotal party, which fluctuated between supporting the ruling party and maintaining its stance as an opposition party.