this article assesses the effect of changes in the lawmaking process on the success of the president's legislative agenda, distinguishing between within-term success (bills that passed during the term) and overall success (including bills that passed after the president left office). With the 2064 presidential bills introduced in seven terms in Chile's presidential system, we assess the impact of changes in lawmaking rules on within-term (59.9%) and overall success (70.6%). Changes that decrease attributions of the president and create more opportunities for executive-legislative bargaining-including concurrent elections-increase the chances of success of presidential bills. the use of presidential urgency motions, an agenda-setting tool, makes bills more likely to pass, but the issuance of many urgency motions undermines the bill's chances to succeed. Presidential bills introduced early in the term and those on issues where there is more policy convergence are more likely to pass.as the devil is in the details, the success of the president's legislative agenda should be impacted by changes in the rules of the lawmaking process. in countries where legislative rules rarely change, differences in how presidents use their toolbox of legislative powers explain legislative success. thus, "differences in uncertainty, not partisan support, drive the variations in chief executives' ability to enact policy changes through statute law" (saiegh 2011, 11). in turn, in places where legislative rules change all the time, the effect of specific changes is difficult to isolate. But in countries with more stable institutional design and party system, seemingly minor changes in lawmaking rules might impact the success of the