Without any substantial constitutional change, Peru has moved during the last five years from a presidential political system, where the Executive controlled the political agenda, to one where the Peruvian Congress has considerable power. This article claims that the trigger for change was the electoral result of 2016, as it drastically shifted the balance of power between executive and legislative. This election gave a large majority to the opposition in Congress, allowing the ge-neralization of extreme institutional weapons such as the presidential impeachment and the confi-dence motion. The corruption scandal known as Lava Jato accelerated the process. The proof that this is a new system is that these repertoires of interbranch conflict have remained in place even if no party has able to hold a majority in Congress during the last two electoral cycles.