This paper seeks to investigate the behavior presented by the deputies’ chamber, with regards to the bills which were sent by the executive power during the legislative term 2002 – 2006. The author tries to demonstrate that one of the most relevant reasons in order that the Government of Ricardo Lagos could fulfill wit success its bills, was the high unity of the governmental party and the heterogeneous action of the opposing bloc. In this way, with the analysis of the votings in room (Roll Call), this article locates each one of the parties and coalitions in a percentage space of approval to the initiatives of the Government, situating to “Renovacion Nacional” as a pivotal party which fluctuated between the government law support and its quality of opposing party.